Booking.com Host Cancelled My Reservation, Now No Refund in Sight

I made a reservation in January 2024 for my trip from May 22nd to May 26th, but the host canceled my reservation without my approval due to an event in the city that raised prices. Booking.com guaranteed to cover the price difference (clearly stated in emails) and arranged a new place for me themselves. They asked me not to pay and to provide an invoice. I provided the invoice on the check-out date and requested my refund. Although customer representative Kurban initially approved the invoice, the refund was not processed afterwards. When I spoke with representative Zelal, she said the invoice was compliant with the rules and that the refund process had started. Later, the finance department rejected the invoice. They then asked me to request a new invoice, which I did from the host again, but they did not accept it. They asked for the invoice a third time from the host and sent him an email requesting the required form. The host got angry and finally sent the invoice as they requested. It's been a month since my stay, and now they're asking for a bank statement showing the cash payment I made. Booking.com is not refunding my money at all. (By the way, customer representative Zelal specifically mentioned that cards were not accepted where I traveled and that cash was paid.) The invoice states that cash was paid. They're not giving me my money back and are trying to blame me for the excessive increase.