3x my monthly account fee deducted. Still no refund after 3 weeks

I requested Discovery Bank to change the deduction date of my monthly account fee on the 18th April. This was to be changed from the 17th to the 27th of every month. This was indeed done but sad to say it was at my costs because Discovery deducted 3x my monthly account fee during the month of April. They deducted on the 17th, 22nd & the 27th April. I have called them on numerous occasions requesting a refund and today is the 10th May and I have yet to receive my money back. Absolutely appalled by the lack of service & feedback I’ve received.