FNB ignoring my Dispute and Outstanding authorisation reversal request

I am so disappointed in FNB. They refused to reverse a debit card transaction after the business I made an order from did not deliver the items I had ordered. The business in question banks with FNB and they refuse to pay me back my deposit. . So I reached out to FNB to reverse the transaction, but they still haven't. I gave them sufficient proof in the form of receipts, Whatsapp conversations, I even told them that I can get an affidavit and open police case if I have to. But they still haven't responded! It's been weeks! I really regret moving from ABSA to this bank.