overcharging on account

I contacted a person at box office through facebook earlier today with only the initials KWM. i have tried over and over to explain to this person that they are overcharging me. i am on a fixed payment plan with dstv and every month they take my subscription. they took my payment of R350 for last months box office and they have added it again to this months debit order. this is unacceptable. i need someone in management to contact me asap. You will rectify this! My payment for month end was R1399.22 then you deduct the 899 fixed payment plan then you deduct the R350 from last months box office rental then you get : R150.22 then you deduct the insurance. now your KWM consultant tells me that my box office was not covered. please show me how you get to calculate it that way!!