First of all, let me say this has been by far our worst experience hosting someone. I am saddened to be dragged into this situation. Doli was not a trustworthy guest, who had another reservation somewhere else and simply tried to bully her way out of ours. If you are reading this answer, I would ask you to please read our other reviews, which are all very positive.
Here's a rough timeline of what actually happened. When we approved Doli’s stay just minutes after her request, she mentioned that she had parallelly booked another place, but that she was going to try to cancel it; yet we never really knew if she did. We found this very odd but decided to go ahead with the booking. The next day after her check-in she completely blew up. She claimed that she could not continue to stay at the place and started knit picking every single detail with absurd complaints. She claimed that there was mold everywhere and that she was allergic to it, and therefore, she demanded her full money back. That day our manager Estella went straight to her to see what the problem was, but she found that they just left the keys on the table and after inspection, found the place exactly as she left it; so, we were sure that they did not even spend any time there. This reaffirmed our certainty that she surely had found another accommodation parallelly to ours; and that she was just trying to find any excuse to cancel ours, and hence the “full refund” demand, when the Airbnb cancellation terms and conditions are quite clear on that. She sent some pictures of the “mold” she found, and let me say that these photos included pictures of unreachable places like the pluming behind the toilet and far corners of the ceiling, clearly just trying to find anything to criticize and with no evidence of mold. We immediately contacted her and tried reasoning in our most polite manner, regardless of her rude messages and terrible attitude. We offered to bring back our cleaning crew (not maids) so that she could point out anything she desired thorough cleaning. We even offered to change the faucets, which indeed had some rust at their base, but which is a common and unavoidable result of the extreme humidity so near to the beach. After this, the black mailing started. She answered our offers saying all she wanted was her full money back, but that if we did not do so, she would make sure nobody would stay in our place ever again and destroy us online, etc. etc. We answered again as politely as possible and told her that we sincerely regretted her threatening attitude and that we would simply follow the Airbnb cancellation policies if she decided not to take our offers and cancel. After this, it turned out that instead of cancelling that reservation, she accidentally cancelled another one she made for her friends. By the way, at the time she did that second reservation, we were also uncomfortable to know it was not for her, but again, we always try to be as helpful as we can. However, when she told us about this accidental cancellation, we compromised and did the best we could by contacting Airbnb and managing to reinstate her reservation without any extra fees for her. After this and out of nowhere, she decided to return to our place. We ended up regretting this decision, as she misused the installations by breaking an air conditioning system (we also have pictures of this) and taking with her some towels when she left. Just before leaving she even claimed in another angry message that she didn’t actually stay in the place, perhaps trying to show us again that she did not like it, but which only proved the fact that she did indeed have another accommodation elsewhere. Again, we really regret to be pulled into this discussion, as we always do our best to be good hosts and have our place, which is our family holiday house, as best kept as possible.