They told us to cancel bc it is a double booking yet no refund was made

We made a booking via booking.com at Ui Views Margate for (31 Dec 2025 to 04 Jan 2026). I tried to make a follow up several times asking if the booking went through and they kept on saying their system is down, only for them to call with a private number a day before in the evening saying we need to cancel bc it’s a double booking. I tried to reason with them but the lady was rude and told me to to do free cancellation I’ll get the refund within an hour or 2. No refund was made and we have no place to stay. They are very unprofessional and ***********. They have inconvenienced us so much bc we could have made another booking but still waiting for the refund.