I tried to get any sense out of Booking.com when i was stranded overseas at an airport, because of an airline mistake. The airline said talk to travel agent - booking.com said talk to the airline …
You may have had a good reason for using Booking.com. Maybe someone recommended this to you?
Although I once used a travel agent many years ago, I now make my travel bookings directly with airlines, hotels, etc. Perhaps for a complicated itinerary I would use a travel agent, but never the on-line ones such as yours.
And welcome to AFF.