A Christian brother and sister from Syria say they have been 'let down' by the Pope after he left them behind in a Lesbos refugee camp despite promises they would be given a new life in Italy.

Roula and Malek Abo say they were two of the lucky 'chosen 12' refugees selected by the Vatican to be taken from the desperate camp and housed in Rome.

But what seemed like the chance of a lifetime was cruelly snatched away when they were told the following day they couldn't go. Instead three Muslim families were taken.

Roula, 22, and her brother arrived on Lesbos on April 1 – ten days after the controversial EU deal to return all asylum seekers arriving to Greece from Turkey.

Their application for asylum is being process and they are waiting to learn if they will be sent back to Turkey.

Stuck on Lesbos, Roula told MailOnline: 'If they can do this for 12 people they can do it for more.

'If you have promised to take people back to Italy will something like registration papers stand in your way?'

Future: Roula, a Christian Syrian, and her brother were they had been selected to go to Rome with the Pope but were let down the following day and are now stuck on Lesbos

Dreams dashed: The siblings, who fled Qamishli, Syria, were not among the chosen 12, because they arrived on Lesbos ten days after the controversial EU deal to return failed asylum seekers to Greece from Turkey

Neither Community Sant'Egidio, the charity which organised the trip, or the Vatican would explain the selection process over which migrants were picked.

Spokesman Massimiliano Signifredi called the incident 'regrettable' - adding: 'The problem here is the three Syrians arrived after the March 20 deadline. They arrived just after the agreement between the European Union and Turkey.

Mr Signifredi said: 'Our staff went to Lesbos and spoke with the people who were selected. But everything was decided by the Vatican.

'The question why the Pope took only Muslims is difficult to understand and he was suffering, I think, because he wanted to do something also for Christians as the chief of the Catholic Church. But he couldn't because there is this international agreement [with the EU].'

The Vatican declined to comment.

Still reeling over her dream being so cruelly dashed, Roula had to watch the three fortunate families board a plane for a new life in Europe while she and her brother were left behind to face an uncertain future in Greece.

Pope Francis, the son of Italian immigrants to Argentina, said the decision to take a dozen to Italy was a gesture of goodwill to set an example to the world to extend the hand of friendship during Europe's migrant crisis.

They are being housed in Rome by Sant'Egidio, which has brought 250 Syrians to Italy since March.

Roula, her brother, 28, and a third man, their friend Samir, also 28, from Damascus, say a day or so before the Pope arrived they were approached by three volunteers believed to be from Sant'Egidio.

She explained: 'They said they would take us to Italy, to pack our bags and to meet them the next day.

Leading by example: The Pope took a total of 12 people back from Lesbos to Greece with him. The leader of the Catholic Church has been vocal over his disapproval of how Europe has handled the refugee crisis

Suspicion: Roula, pictured with Malek and friend Amir, admits she was relieved in one way, as she feared the three who approached her could have been organ traffickers

Devastated: But Samir Hanna, a 28-year-old refugee from Damascus, had no such fears, and was left crushed when he was left behind in the camp, called Kara Tepe Square

'It was so secretive – they didn't announce it to anybody and we were told to keep it a secret.

'It seemed so unofficial – we didn't know who they were or if they would really take us,' Roula added.

'I thought they might be organ traffickers – we had no idea.'

Samir had no such doubts when he was approached, however.

'I was so excited to go to Italy - it was such a relief,' he said. 'They offered me my future on a plate, and then 24 hours later they took it away.

'They had even told me that after a few months I could be reunited with my family and they would arrange for them to come from Damascus and join me in Italy.'

But the next day they received the crushing news that their places were given to another family.

The reason they were given was because they had arrived in Greece after the March 20 deadline for the EU deal.

The Pope told reporters on the plane back from Lesbos that it had been the idea of one of his aides and that he had immediately agreed.

'I felt the spirit was talking to us,' he said, adding that 'everything was done according to the rules', with documents provided by Italy, the Vatican and Greece.

Asked why they were all Muslim, he said there was something wrong with the papers of a Christian family that had originally been on the list.

All 12 migrants from three families have spoken of their delight at being set up in their own flats in Rome capital and given Italian lessons.

'It was an amazing feeling [to be leaving the camp in Lesbos] because this was our big dream,' said Hasan, a 31-year-old a garden designer who fled after the Syrian regime tried to make him join the army. He is now in Rome with his son Riad, two, and wife, Nour.

'When we came here to Sant'Egidio everyone has been very helpful and kind. Now we have our own room [apartment] which is just for us.

'We have been treated very, very well. We really feel now at last we are safe.'

Arrivals: The lucky families that were chosen to go with the Pope - Nour and Suhila were among the three families from Syria who did get to Italy

New homes: The families all have new lives in Italy while Roula and her brother are 1,200 miles away back in Lesbos facing an uncertain future

But 1,200 miles away in the sweltering makeshift camp with the rats, snakes and rubbish of those who remain faced with the prospect of being returned to Turkey is Samir.

'I was very disappointed,' he said.

The siblings are trying to stay positive as they want to travel to Germany where their mother is living. But they are at a loss to explain why Sant Edigio volunteers appeared to 'play god' and got their hopes up only to let them down.

'We're happy for the families that went of course,' said Roula, who is hoping the charity stands by its promise to fast-track their applications and come back for them, but it is no guarantee.

She went on: 'We don't care for one country over another – I just want to be with my mum.'

Roula and Malek left Qamishli, which is in Syria near the Turkish border, in March, in fear for their lives.

'They killed the Christians in Raqqa we heard, so of course we had to leave,' Roula said.

Malek added: 'We stayed as long as possible, because it's not easy to get the money to leave Syria. It takes you 50 years to buy a house so you don't decide to leave it in a minute.

'We were clinging to the hope that it will get better. We know that as soon as we leave the house people will come and take our stuff. We know we can't go back.

Residents: Kara Tepe is the preferred camp for those trapped on Lesbos. Currently there are 900 people living here, who have all been termed 'vulnerable', and have their applications on hold

Waiting: Despite it being the better option, the atmosphere in the camp is still tense

Escape: All three families selected by the charity were taken from Kara Tepe camp to meet the Pope in Mytilene before jetting off to their new lives in Rome. Pictured: : A Syrian mother with her three children

'We wanted to finish university – I studied law and Roula was studying to be a primary school teacher.'

The pair had hoped finishing their education would give them a better chance to start a new life in Europe, but Roula had to abandon her studies to flee.

Samir left Syria for Turkey late last year, just before Christmas, after he escaped being forced to join President Assad's army fighting a war he doesn't believe in and do his military service.

'They force you to sign up and they make you kill people – if you don't, they kill you. I had to leave,' he told MailOnline.

Like many Syrians, he first tried to make a new life for himself in Turkey, despite having to wait for months on the Turkish-Syrian border, as Turkey has abandoned its open door policy to allow refugees fleeing the violence to safety.

'I was in Istanbul for three months trying to find work. I tried so hard, but it was impossible. People look down on you there – they don't want to hire Syrians,' he said.

So he joined the thousands of his desperate countrymen and the now standard fee of €2,000 to cross to Lesbos on a rubber dinghy.

In Kara Tepe, the camp named in Turkish because it is above the black cliffs smugglers tell their newly branded captains to aim for, Samir, Roula and Malek joined 900 other refugees deemed vulnerable and have their applications on hold.

Much preferred to the feared Moria detention centre where migrants are sent upon arrival, the camp is nestled on hillside surrounded by olive trees, and is exclusively reserved for families who have vulnerable members – those who are disabled, have severe trauma and are survivors of torture or rape, or are single women, pregnant or lactating mothers.

Frustration: For many, the disappointment of getting so far, only to get stuck once more has been hard to deal with. Pictured: A Syrian man listens to music at the camp

'Like animals': Refugee women complained of snakes, and said they were being treated like sheep, forced to live in the camp on the island

Relaxed rules: Inhabitants are free to go to the supermarket, as long as they have written permission, and are served meals twice a day. Pictured: A disabled man from Afghanistan

Inhabitants are free to go to the supermarket, as long as they have written permission, and are served meals twice a day.

NGOs provide humanitarian assistance and volunteers help out with clothes distribution and activities for the bored children.

While the residents are free to leave, if they are caught outside the camp without written permission, they face deportation or will be moved to the Moria detention centre.

But it is miserable and the atmosphere is tense.

For many the disappointment of having made it to Greece and across the water to be told they cannot go any further is too much to bear – made worse by the conditions.

'We get told that we are lucky to be here in this field,' grandmother Kawther Yousef told MailOnline, 'but what are we, sheep?'

'This is the fifth snake the boys have killed – they're all about this size, they're babies – but where is the mother?' another grandmother called Susan from Kobane added.

The group of women are all alone – their husbands have either died in the fighting or they have gone ahead to Europe and are desperate to be reunited.

All three families selected by the charity were taken from Kara Tepe camp to meet the Pope in Mytilene before jetting off to their new lives in Rome.

But for the hundreds left behind, the idea of selecting such a small number people seemingly at random is a hard pill to swallow.