Had a rough run with Booking.com too, especially in the Caribbean. Even with a confirmed reservation, anything that isn’t pre charged feels shaky. Properties cancel at the last minute, and Booking.com just shrugs because technically the hotel hit the cancel button.
We booked Grand Sirenis Punta Cana months out and a week before the trip one of the rooms got canceled for a “credit card issue,” even though the same card worked fine for the other rooms. By the time we tried to fix it, they were “sold out,” and we ended up scrambling for something else at almost double the price.
At this point I just use Booking.com to find places and then book direct. A lot of hotels really hate paying OTA commissions and seem way too quick to ditch those reservations when demand jumps.