Oleg T.

Gonna tell you how hotel can easily cancel your booking, even a "non-refundable", using a disreputable trick.
A hotel tells booking.com support that it doesn't want to see you. You had any kind of conflict that's why hotel refuses to settle you.
In one case hotel told booking.com that I was drunk and screamed loudly. Nonsense, I don't drink alcohol at all. And why then I would call the police that day?
Booking number *******, supposed to check-in on 1st October if some stuff of priceline wants to see the shame of their managers who forever lost their loyal client.
The original reason why the guest house did so is because I demanded a sales receipt for paying amount in cash. Under local laws a client has right to demand a receipt and if so seller MUST give such a receipt. But this guest house refused to give receipt and told me to find another hotel. And manager=owner Larisa created a lie how to cancel "non-refundable" booking.
I've sent statements to police and tax authorities to invoke the responsibility for tax violations and illegal business. It was a small guest house in russian village which manager=owner stated that all guests paid nothing and all lives for free as personal guests. 18% of VAT is so big during economic crisis.

Anyone can get now that "non-refundable rate" is only non-refundable when YOU wants to cancel booking, not when hotel wants to avoid paying taxes and you are irritating client who wants to be protected when you are paying money. Btw, hotel was not accepting credit cards despite icons on booking.com page, which is normal for a russian guest house in a village.
And booking.com covers such "business" because it's not you who pay 15% and higher comission to booking.com from each night price, it's someone else. Russian-speaking managers in support (sitting now in places like Berlin, I have plenty of their funny surnames: bulgarian, latvian, western-ukrainian, etc.) treat russian clients like escaped refugees happily run away from motherland and they definetely wants the worst to remaining ones.

Previously there was the other case throughout the history(80+) of my bookings. I found out what really happened about half a year later talking with support about other case and in common.
Had 2 stays at hotel in St. Petersburg. 1-2 nights each. And each stay I put bad marks in reviews due to intolerable unconveniences like smoking smell in my room, etc.
And made a 3rd booking a bit later at a sale off price knowing about some problems but at least I already knew it and I was prepared.
Unexpectedly I found out that 3rd booking was cancelled. Booking only noticed that it was due to "misunderstanding" with hotel. I've contacted with hotel's manager and found out that it was because of bad reviews.
Later booking.com support told me that hotel sent to booking a slander that I behave badly like screaming at personel and other nonsense (at 1 day stay, a-ha).
And funny part was that the review about 2nd stay was posted on booking.com at 19th January and the hotel sent that slander to booking.com at 20th January (date was named by booking.com support). Coincidence? No, just stupidness and loss of a customer.

So, dear hotels and small guest houses with no reputation, tell lies and avoid e.g. overbooking easily. Just say that you had a conflict and a "non-refundable" booking is cancelled, free for you.