Avon Credit Control does not want to refund money transferred by mistake to their account

I've transferred R2400 to Avon by mistake on 24 July 2021 via a Nedbank App, when I request your credit control, it seems as if no one wants to look at that account as they respond with the same response. We have submitted all the be they requested for. They have been sending us from pillar to post as if my money has just gone down the drain. I am really stressed and frustrated since no one at Credit control seems to care. I need my money to be refunded back to my account. Their consultant has sent a letter, proof of payment, and proof of bank account as requested but nothing is happening. I have been trying since Monday with no luck.