Hotel ARENA am Zoo in Frankfurt am Main

We found the room very dirty and smelling of tobacco. There were cigarette butts under the bed, sticky stains on the floor and furniture as if from some liquid, the shower door did not close and you can see that it had been dismantled and they had left the piece that had fallen right there. Also, the heating didn't work and it was very cold. We went to the reception but found that it was already closed (it was approximately 6pm), although according to the page and the sign on the reception door it should close at 8pm. We called the emergency number and when we managed to contact them they told us that they couldn't do anything because it was a holiday (New Year's Eve) and that they would solve it the next day. In the morning, after having spent the night frozen, we went to reception and explained again what had happened because no one had informed them and they said they would fix everything. Also, in these two days we talked to trip.com staff and they tried to help us. The hotel told them that it would also fix everything for you. That afternoon when we returned we found the room in the same condition, except that the bed had been made. The heating still didn't work, the shower rod was still on the floor and the cigarette butts were still under the bed. Again, violating the hours on the sign, the reception was closed so we called the number they had left again, this time without being able to get a response. The next morning we were leaving and we repeated to reception everything that had happened. Their solution was for us to write an email explaining what had happened. We sent it and asked for a refund (at least partial) but they don't want to do it because everything is already fixed, according to them. A shame and a terrible experience, especially because of the cold.