Over charged

I received R50 voucher from Debonairs, On the 29-01-2023 I purchased pizza online that cost me R189 and I used my voucher then the difference was R139 . I used my card details to make a payment but the money that was taken out was R189. I went to Debonairs Delft mall to collect my order and I show the manager and on the slip R50 is there , how ever it has not be deducted. The manager said I must contact my bank, I told him that my bank doesn't have any thing to do with this , the money has been deducted by Debonairs. So on Monday 30-02-2023 I contacted customer service they gave me email address to email slip and the statement, which I did on the same day, but no response till today