Booking.com complaint: Cancelled a six room booking

In September 2021 I reserve six rooms for family travelling from abroad for my mom‘s memorial service for those That could not attend a funeral from the 2nd of June to the 5th of June .
on the 18th of April this year that whole booking was cancelled with no warning all rooms had been paid for upfront. this is now the same weekend the Queens Jubilee is to take place this means I have to find rooms for 21 people in a very short space of time. when I was told about the cancellation I was told the money would go back to my account I tried to explain that that account had now been closed as it was an executors account for my late mother. I was not listen to, it is now the 3rd of May and no refund it’s looking like it’s going to take place and they will not take down new bank details so that when they receive the money back they can automatically send it back out to myself. As you can im again this is all ver distressing. I love over 300 miles away from the event.