Theft of pre-paid accommodation money

I made a payment in March 2023 via Booking.com to accommodation in France called Pixel. They took my money and acknowledged through Booking.com receipt of the money. When I cancelled withing the cancellation time they told me it would take 4 weeks to get the money refunded. I have now been waiting 3 months and Booking.com are giving me the run around and no one is paying me back. Do not pre-pay accommodation with booking.com unless you are willing to throw the money away.