Refusing to refund the money

On the 30th June 2021,. I was paying the store through EFT and I mistakenly transferred R7000 instead of R700. I've been trying to get a refund from the store since the 1st of July. They asked to send a bank statement and copy of my ID which I did. I phoned after a week only to be told they can't refund money to old mutual bank and I was asked to provide the with a statement from a different bank. I did send it. It's been more than a week now. Phoned them this morning again . I got told the same story" the person who is dealing with your issue is not at work" . Please help I'm frustrated . It was a long month