@Inna22 I cannot believe that! I'm so angry for you!!!
Reminds me of the bed bug stories where the guest still wants to stay but complains afterwards.
Bottom line, if the problem is bad enough the guest wants a full refund, the problem is bad enough the guest should leave as soon as the problem occurs.
As someone else mentioned, it's a lesson learned, unfortunately due to deceptive guests. The next time a guest complains about something I guess we need to spell it out like this:
GUEST: There's a bug in my room.
HOST: Oh no! I'm so sorry! I will remedy the situation asap or I can arrange to have you moved to another Airbnb. Is the situation bad enough you feel uncomfortable and would like to leave?
GUEST: Well, no, if you could just take care of the bug.
HOST: I'm on it and will offer you 10% off tonight's rate for your trouble. Are you sure it's not bad enough that you'd want to leave the property?
GUEST: I'm sure.
Probably still wouldn't matter to CS, but at least you have the guest admitting it's not bad enough for them to leave. I'm still fuming for you! Ugh.