@Helga0 I think much of getting a review taken off depends on the Airbnb agent who happens to respond to you or your guests. We similarly have had all 5-star reviews for over two years straight, including several this spring and summer. Then we had a "crazy" guest, to use your wording, arrive from Spain with two elderly relatives whom, we deduced quickly, would have preferred that he had taken them to a hotel rather than an Airbnb. On the very first night, he was complaining that there was no maid service, that there was only one Spanish TV channel (in Portugal--but we have 200 channels plus Netflix access), and so on.
Eventually, he fabricated this story that first night about a supposed "attack" that had taken place in which he claimed that some mystery man had thrown rocks at our window in the middle of the night and terrorised his relatives. He also broke a vase inside our house and claimed that a rock had somehow penetrated the window and window grill without breaking anything but the vase (which is physically impossible). He even called the police to try to get legitimacy for his story.
This was all an excuse to try to get a full refund. The police filled out no report because they told us, clearly, that no such attack had happened. We also called the security at the condominium and they told us the same, and Airbnb similarly told him and us that he could not receive a full refund after checking in without providing evidence. We tried to help him out as best as we could, but he had also booked our place for 9 days at peak season, and if he left and expected us to give him a full refund, we would have lost all that rental income and would still have had to pay Airbnb their fee, as they were not relenting.
So, the guest left and vowed to write us a bad review, and he did. In the review, he changed all the facts from his story, and we had all of this in writing on the Airbnb message system.
Guess what? When we sent all the evidence to Airbnb, including where the guest had promised us that if we could get him a full refund, then he would write a good review for us (which supposedly violates the Airbnb review policy), the agent didn't even acknowledge any of it. Like you, we had had nothing but 5-star reviews before and after this guest checked in and out, and while the first few agents we had spoken with at the start of this case were very understanding, this one dismissed us outright and sent us what looked like a form letter: "Upon review, we have decided that the guest's review can stand." He did not refer to one single point related to our case. Then, to add insult to injury, we were told a week later that we would be losing our Superhost status until the next review in October, because of this one bad review.
We naturally protested with this agent, but he simply told us that if we were unsatisfied, then we should contact Airbnb feedback and gave us a link for contacting them. But then he added, "Please understand that you may not get a response from them."
And we heard nothing.
So, there you go. We understand now that when dealing with Airbnb agents, it is often "the luck of the draw." Some will sympathise, but others will side with the guest because it is easier--even if that guest is "crazy."
In the end, Airbnb is a business, and so if that sometimes means satisfying its customers while throwing its hosts under the bus, then some agents will choose that route. We are glad, however, to hear that it seemed to have worked out for you. Not all the agents are bad, but they are human--and as we know, some humans are just plain lazy and are thus going to choose the easy way out.