@Kemal20 Which of your listings was this for? I see that the first two do not list air conditioning, so if it was one of those, there is no way the guest should have been allowed to cancel and be refunded on that basis.
Your third listing does say air conditioning, so if that was an error on your part, or it wasn't working, then the guest did have a legitimate cause.
And I have to say, I don't know how your pricing compares to other comparable places in your area of the world, but they seem way too cheap for what you offer and the number of guests they accommodate. That will attract poor guests. It's better to raise your prices, even if it means a few less bookings, than to get lots of bookings and bad guests who scam for refunds or disrespect the place. I charge more for a private room in my home for one guest than you do for an entire apartment that sleeps 3. And my guests tell me it's great value.