Bad service from Booking.com

Booking.com is so useless. I made a booking for accommodation but the owner informed me it was fully booked, she advised that I make a cancelation and I did. Booking.com was supposed to give me my refund but even today I haven't received it. When I call them they keep on saying I must submit supporting documents on the link. I explained to them that the link doesn't work. They keep telling me the same thing when I call them. This happened on the 15th Nov 2021 but even today the 13th Dec 2021 I still don't have my refund. I wouldnt advise anyone to use Booking.com, they are useless.