Refund issues

I have been trying since March 2024 to finalise a refund through booking.com. They have assured me numerous times that the payment had been processed (payment was supposedly paid April 2 2024) but cannot provide me with a proof of payment. They keep telling me check with my bank who say it hasn’t been processed into my account as of yet.

According to the website it takes 2-5 days to reflect into the customer’s bank account- this has now been over 7 working days.

I have been in constant contact with them to no avail.