Incorrect Billing/Accounts

I am very disappointed with the billing system at Totalsports, I activated my account on Saturday 18/02/2023 and I purchased a cellphone for R1499 which I was told that I need to pay a 30% fee upfront which I did, I got the phone and my receipt which indicated that I could still purchase for R3700 on Sunday I went to Jet and made a purchase of R239.90 and my receipt indicated that I can still but for R1962 which is incorrect when i called the customer service line yesterday I was told that my purchase at Totalsports of R1499 on saturday was duplicated and 1 is hanging that's why my purchasing power is sitting on R1962 funny enough my balance owing is R1289.28 and when I add the balance owing and the amount left to purchase they do not add up to R4750 which was my credit that was granted when opening the account. I was told that I need to go back to the store to have the transaction reversed. Why must I go back to the store when its not my error?, so I must take my time to fix a billing error that is not my error?. I need total sports to fix this ASAP otherwise I will just pay off my outstanding balance and close this stupid account because I have had it less than a week but already I am encountering issues which is not customer service to me.