Horrible experience with guests

[Bente47]

Hey guys, 

I just had an horrible day due to a guest who was trying to stay with more people than he booked for. After I found out he tried to cancel (which was not possible) he harassed and intimidated me during the hole day through messaging. I tried to get help from the customer service but they've told me that if I would give him a full refund he would probably stop... I'm flabbergasted and didn't feel save anymore (the B&B is next to my house). They've called me after 8 hours and somehow Airbnb cancelled the booking and fined me 300 eur... it's the other way around I guess. Did someone have an experience like this? I'm thinking about leaving Airbnb because I should feel save and support by Airbnb.