Waiting for refund since March 2019.

I ordered books online in march 2019. The very next day I cancelled the order but they had already processed the payment. I've sent numerous emails to them for my refund but they keep tell me they waiting for the goods to be returned to them by me. I keep telling them I have not recieved any books from them. Its was lockdown 2 weeks after the order and cancellation was made. I've not recieved any books from them. It's now almost a year I'm battling to get my money back from them. I'm very frustrated. Ever sorry I placed the order with them. They are dont care about their customers just quick to process the payment.