It must have seemed like a dream adventure: a two-week festival on a beach in Central America, camping out under the stars at night in what organisers called “paradise on Earth”.

But because of the coronavirus outbreak, a group of 30 British workers and volunteers at the festival are stranded in a makeshift camp facing nonstop rain, a difficult relationship with the British embassy, and a sewage problem.

The group were taking part in Tribal Gathering, a festival in Panama billed as “an amazing indigenous musical journey through time and space”.

Local health workers check attendees of the Tribal Gathering festival rock in Cuango. Photograph: Luis Acosta/AFP via Getty Images

The festival was put in lockdown in mid-March after Panama declared a national emergency following its first coronavirus case. That meant many attendees missed their flights home. Some managed to leave the site and catch later flights, but others are still there.

Peter Grant, from Somerset, who volunteered in the kitchens at the festival, praised the organisers’ work to take care of them but said the Britons had received insufficient support from the British embassy and feared they could be stuck for months.

“We were in limbo for about a week,” Grant said. “Initially the embassy offered buses to Panama City but we only had 12 hours to decide. We also had no guarantee of being able to get a flight. In the end some of those people got their flights cancelled while they were in the airport queue.”

He said people were not keen to leave the site without knowing what would happen to them next. “At the time the beach was the safer option for us, and we were never offered those buses again.”

At first, he said, the beach wasn’t too bad. “The festival organisers were great. They were delivering food and provided us with big tents to shelter in. There was also running water.”

Then the weather changed. “It rained nonstop for a few days. There was no sewage system and disgusting water was pouring everywhere. Not only that, a few people have mental health issues and they started really struggling.”

Tents at the makeshift camp. Photograph: Chris Hemmings

He said the group made repeated attempts to speak to the embassy. “They just kept giving us the same options every time, saying ‘hold tight’ or giving us expensive hotel options in Panama City with no means of getting there. And there were no options for flights home.

“We’ve faced bureaucracy from Panamanian officials, too. You need permits to move around and they don’t really want Europeans going into the city.”

Hannah Bates, from Brighton, who was part of the production crew for the festival, was one of those who got on the buses sent by the embassy on 20 March. She is now staying in an Airbnb in Panama City and is quickly running out of money.

“The embassy had written to the production manager saying they’d send buses to collect British nationals to go to Panama City, and that this would be their last chance to get out of Panama,” she said.

In a video seen by the Guardian, a British embassy worker tells her and others on the bus: “You should be aware flights will be suspended internationally from Sunday [23 March]. If you don’t get a flight by Sunday, you won’t be going anywhere for at least 30 days.”

Bates booked an overnight hotel and went to the airport the next day to catch her flight. “At the desk they confirmed that I could get to New York for my layover, but that all flights out of New York were cancelled. I didn’t feel safe leaving to stay in New York as I couldn’t get back to the UK from there.”

She then tried to get a flight via any route back to the UK but was told that the airport would be closed the next day. “I sat on the ground and broke down. I felt alone and scared in the airport.”

In a now-deleted post on Facebook on 28 March, the embassy said there was limited availability for Brits on flights going back to mainland Europe, but “none of these flights is destined for the UK and onward connection will be the responsibility of anyone seeking to go home”. Travellers would have to report to the airport at “very short notice” for these flights, which for those stuck at the beach was not possible.

Two days later the government announced a £75m scheme to help repatriate Britons stranded abroad, and suggested citizens should get on any available commercial flights “without delay”. For those left in Panama, flights out quickly became fully booked, were cancelled or were too expensive.

This week Panamanian authorities announced a 30-day extension to its ban on international travel into and out of the country.

“The embassy is a joke,” Bates said. “There was a glorified lift-off site and that was it. There’s been no help with food, accommodation, nothing. We’re told there are no further plans of future flights for Britons leaving Panama, and now we were being offered lifts back home on flights put on by other European countries. Then how do I get home from there? I’ve lost three flights already; I’m not in a financial position to keep booking them. We’re facing months here.”

The Foreign Office said it had helped 85 people return to the UK. “We are in regular contact with members of the group remaining at Tribal Gathering,” a spokesperson said. “We have provided details of available accommodation and have offered safe passage letters to assist in moving there.”