Annoyed!

On the 27th August , I bought a few groceries from Checkers on the APP. The mayonnaise was on special ,however on when the receipt came through I was charged the normal price of R49.99. The sanitary pads was buy 3 pay for two , I only received two packs. I phoned the call center and advised them of same. I was advised that I will be refunded within 48 hours and still nothing. ***. I then called on Monday and was advised to wait 48 hours? Its been 384 hours , still no refund!