Bad service Jet Mayfield

I went to Jet Mayfield in Daveyton today to do an exchange and refund, I bought using moretyme and didnt have the my card because I didn't think they'll need it, there was 2 ladies at the till, I think one of them was a supervisor I was told they will assist me and do a cash refund but now the cashier did not have cash and I was to wait for another cashier who was coming back from lunch in 15 mins, I come back after 15 mins and had to explain again to the second cashier that I didn't have my card and I was told they will do a cash refund and the supervisor is there and not saying anything, now I'm going back and forth with this cashier but the supervisor I spoke to is just there and not explaining to the cashier, after sometime she jumps in and asks what the issue is, now I need to explain again that this what she told me earlier on she then tells the cashier to do the transaction, as the cashier is exchanging the item she tells me it's now marked done, I bought item with R150 but was now marked to R100 they did the refund for other item which I bought for R389, and the supervisor (Pretty) tells the cashier (Olivia) to only give me R389, took my stuff and left because I was already annoyed, so what happens to the R50 do they take for themselves or what cause I didnt get it?