Still no refund from Booking.com

I have booked accommodation in Turkey through Booking.com on 2 October 2023. I received an email early the next morning that the accommodation was not available any more, although i fully paid for the accommodation and my booking was confirmed by Booking.com. Booking.com promised me a full refund of 630 Euros and I had to make a new booking. This unfortunate event happened nearly two months ago and I still have not been refunded. And what makes the whole situation worse, is the fact that it is nearly impossible to contact Booking.com. The email address I used to follow up with them is now not functioning any more. Messaging them ended up in reference to the accommodation itself, which I have no dealing with. Contacting the international +44 number result EVERY time in the call being dropped (And they never call back). The situation reminds me of somebody owing you money and fleeing from you, while putting all possible hurdles in your way to stop you from getting hold of them. Worst part to me is that Booking.com was my preferred service provider to book accommodation through before. I also have a question why I need to wait 30 working days to be refunded for a mistake on their part???? But we are now nearly two months after the cancelled accommodation and I still have not been refunded. What steps do I need to take to get my money out of them????