Relatives of the 12 people killed in December when a truck ploughed into a Christmas market in Berlin have expressed their dismay at the negligent way they say they have been treated by German authorities.

About 50 people who lost loved ones in the Islamic State-claimed terrorist attack reportedly told a private meeting called by Germany’s outgoing president, Joachim Gauck, and the interior minister, Thomas de Maizière, they felt abandoned at a deeply upsetting time.

Relatives said the first official communication they had with authorities was a bill sent to them by the coroner’s office. The letter reportedly included a warning that if the bill was not paid within a certain timeframe, the recipients would face legal action.

One said that when she received the letter she had thought at the very least it would be a letter of condolence from Berlin’s mayor.

A spokeswoman from Berlin’s town hall, Claudia Sünder, said the mayor’s office had immediately taken responsibility for the coroner’s bill when it was brought to its attention.

But spontaneous letters of condolence had not been possible, she said, because the list of names of the victims and their relatives was not immediately released. “The fact that our hands were tied was terrible,” Sünder said.

Other family members said they were disappointed an official memorial service had yet to be planned two months after the attack.

Relatives also reported how they had had to scour Berlin’s hospitals for missing loved ones as there was no central place they could visit to deal with their inquiries.

Many said the lack of access to information contributed to their already considerable distress.

Those who were certain that their family members were among the dead said they were prevented by security personnel from entering the Kaiser Wilhelm Memorial church on Breitscheidplatz for a religious service held the day after the attack on 19 December.

The reason they were given was that high-ranking German politicians – including Gauck – were among the guests.

According to the papers which reported on the four-hour meeting at Gauck’s Bellevue Palace, the president told the relatives he was distressed to hear they had been unable to enter the church and that he had not known about it at the time.

The victims of the attack included seven Germans, an Italian, an Israeli, a Czech and a Ukrainian, as well as Lukasz Urban, the Polish driver of the truck whose vehicle was hijacked by Anis Amri.

Fifty-six people were injured. Amri was killed on 23 December in a shootout with police on the outskirts of Milan.