Dstv - Wrongly billed according to their system

From last year October the problem started when multichoice start to bill me twice every month. I went and cancel my debit order with them and pay cash every month. I am paying R 1500.00 a month but every month my services is being disconnected. I send how many e mails to their account department without any responses. I went into a dstv agent were i spend almost 3 hours to try and sort out the issue and the person there were not being able to go back so far but she did pick up from December the system is billing me every month incorrectly. I once again called in and i explained to the call centre agents in their head office what the lady picked up and she also checked it and confirm it. Gave me the right amount and i went and pay it. Yesterday i once again paid my account according to what the system says to my surprise this morning my machine is once again disconnected. When i call in to query the lady says sir you still have an outstanding amount of R 1200.00 and therefore we can not reconnect your service. From last year untill now i paid every 5th day a reconnection fee of R 50.00 everytime they reconnected the machine. So it works out plus minus R 250.00 a month just on reconnection fees that is not even my cell phone bill and still the problem is not sorted. Please assist in this matter. I would like them to give me at least one years free viewing for all this trouble