Over charge and refusing to pay back my money

I ordered food from MrD on 29 May 2020. They deducted R900 off my bank account in stead of R300 and no order was delivered. We contactedthem immediately and promised that we would get a refund within 2 days. Its been 2 weeks now, several phone calls, emails and promises and Im still awaiting my refund. ABSOLUTELY SHOCKING. I WILL NEVER PLACE AN ORDER WITH THEM!!!