Increased installment amount

My dstv account number is ***0. My services were disconnected this morning I called multi choice and asked them why. They reconnected my services because they confirmed that an amount of R972 was received on the 1st of May. Earlier this month on the 10th of May, Ispoke to Gugu who confirmed that they received my installment, plus I have made an additional payment of R311, which then brought my account to a credit. I was advised that the amount due on the 1st of June will be R875. To my surprise I'm checking the amount due.. I'm now seeing an amount of R1800 and I don't know where the amount is coming from. I have been on the phone with multi choice every week and I am not getting any joy everytime I speak to them, cause they all have different stories. I was told that my matter will be escalated to the finance department, however it seems like my request was not attended to.