Pathetic Customer service from Complaint Manager as well Cashiers Rachel and Annah

Yesterday 10/11/2020 I went to Pick and Pay Silverwater in Silverton. I bought bread and pick and cooldrink. I have ask the Cashier, Rachel Mathabathe If she can give me R100 cashback. After I swipe my card, I saw her giving me R500 back. I have asked her why are you giving me R500 instead of R100 that I have requested. The transaction did not register on my phone yet. Then she handed over the slip and I saw that instead of the R100 she made a cash back of R500. I have explain to her that I did not want R500, I said clearly to her 2x times R100. She said to me there is nothing that she can do now I need to take the money. I said to her please call the Manager because I am not sure how are going to fix this matter but I am going to go to an Atm to deposit the money back into the bank account for an mistake she did. Instead for calling the manager, she called Annah. Annah came and said no problem we will deposit the R400 back. She took my FNB card and pay back the money. Annah did not say to me that I will be paying bank fees of R19.95 for a mistake Rachel did. Last night I saw on my bank transaction only R380 has been back in my account. I am not going to be responsible for paying bank charges for a mistake that Anna and Rachel did. I need my full R400 in the bank because that Is the money I gave her to deposit bankI am not going to pay the bank charges for a deposit. This money should be paid out of Rachel or Annah’s pocket.Today the Complaints manager phoned me i have explained to what happend. After listen to me his answer is Annah has to pay it out of her pocket. She must put in your bank account the R20.NO sorry for the mistake, NO we apoligize. No I Spoke to Annah and Rachel. Just annah needs to pay.My question is how will Annah, DO i have to come back to the store. Where will annah get my bank account number.