Ibis Budget Bremen City Sud

We’re a family of 4 (6-years-old twins), and booked a room for one night, arriving Aug. 14, at Ibis Süd Habenhausen in Bremen, Germany, on 14th August 2021. By mistake we booked a room for 3 persons (for only 1 kid). When seeing the mistake, we tried to contact Ibis immediately by phone (no one answered) and email to ask if the kids could sleep in one bed. Email was not replied until 1 day before our stay, when we were already on the way to Bremen, so we took for granted that our suggestion was accepted. With our booking code we could enter the hotel. Only then we checked email and saw their reply recommending us that we should book some other hotel!? When carrying our luggage to the room, at one point my husband forgot to wear mask, one of the staffs (probably Indian) ran after shouting that he should wear a mask; fine, my husband put it on immediately, however, that guy himself didn’t have any mask (!), so what’s the point of the staff screaming? The day after, when we checked out, the same cleaning staffs were there and they realized we had stayed with 2 kids. We told them of our email to the hotel but they didn't show any understanding, however in the end we finished our talk and left. The man from yesterday, still no mask, stood at the entrance of the corridor and listened to the conversation. When we passed him on the way out, he started to raise his voice and stirred the issue again. He called us names, “cheaters”, “you Swedes” etc., he even threatend to call the police! Later on he shouted at my husband “ar*chloch” (as*hole). I was so angry and tried to take a photo of the man and asked for his name but he disappeared quickly in a room, once again without mask, other staffs just told us to leave because of “over-stayed”. Does overstay of a 6-years-old kid mean we should be threatened with police, be called names and be insulted like that?