customer made reservation 6pax in one room

I have a customer who did a reservation and not well made

I need some help

Anyway I am new but I didnt know that this would happens

They booked 1 room for 6 people! Not refundable also

Trying to contact them by phone but the phone number is wrong

I sent many emails but not reply

I contacted booking.com but not reply since few hours already 

I dont know what to do, shoud I give the money back?

I am afraid they will go to the place  today but there are already people in the mobilhome, not possible to put 6pax



Blagoje Acho

How did they manage to book the mobile home if other guests are already there? If your setings dont allowed 6 people how did they booked for
6 people?