Incorrect balances

Dear RCS I have a game store card. My statement in Feb states that I owe R3, 974.94 available credit was R1, 273.06. I made 2 purchases at checkers for R306.74. My balance is suppose to be R4, 281.68 instead it has ballooned to R4, 607.10.

My basic accounting knowledge states that balance is R4, 281.68 - R325.85 (installment) = R3, 955.83 then add R325.85 since the debit order returned unpaid R4, 281.68.

Available credit was R1, 273.06 - R306.74(purchases) = R966.32. R966.32 + R325.85(instalment) = R1, 292.17 - R325.85(returned debit order) = R966.32.

Why is available credit R640.90? It means R966 - R325.85 = R640 (This is incorrect, why are you subtracting??) Why is the balance R4, 607.10. it means R4, 281.96 + R325.85 (why is the instalment being added again)

R3, 974.94 + R306.74 = ??? Why is the balance R4, 607.10???

Now I am being told that I must have a calculator to do calculations!!! I am not willing to agree to incorrect figures! Never!! Your customer services just takes what is on the system then gives it to a customer??? Now tell me how did my balance get to R4, 607.10!!

Balance is R4, 281.68 including the 2 purchases of R306.74.

Where is the additional R325.85 coming from??

I have sent someone to pay R350 today.