@Goran70
Goran, I can tell you that you are unlucky that this has happened, it is not your fault and somebody should be held responsible......but let's for a minute look at the reality of your situation.
The guest has broken the foot off the bed, the bed is still fully usable, it just doesn't look the nice bed that it did before this guest.
Airbnb are going to skirt around this issue, they will say that beds are subject to wear and tear and Goran, what Airbnb will do is tie you up in emails, information requests, purchase documentation and all this will do is frustrate you and it will compromise your upcoming bookings as you await for some sort of positive action. It is simply not worth it Goran!
If this was me in your situation, I would go to your local bedding shop straight away and purchase a 'valance' that will fit over your mattress. It looks like a mattress skirt! Do this before the next guest arrives and make your bed up without worrying about the base.....put the base away somewhere. You will have time to make repairs to it at your leisure when you don't have incoming guests.
Goran, as hosts we can stand on our principal and shout to the rooftops that Airbnb should take responsibility for their guests.....and maybe they should. But I have had damage done here in my property, and what I did was put my listing amount up by $5 per night and the extra money has gone into a damage account. Goran that account now sits at over $2,500. If someone breaks something major of mine, I do not expect Airbnb or anyone else to cover my back. I just fix up the damage and get on with the business of hosting the next guests.
I am sorry that this has happened to you Goran but what you need to do now is take control of your hosting business......don't wait for others to tie you up in knots! Firstly, a valance will cost you less than $20 and that gets you back to a position where you can offer a quality item for the next guest.
Mate don't let others frustrate you out of your living, take control and put things right.....ok!
Cheers......Rob