Bad Bad Service

Good day<br> <br> i have been having a problem with my decoder it writes that my account is arears and the account was paid which was 340 but it was paid under my sisters details ( *** ) whom she doesnt have a decoder and i called several times to the customer care line for DSTV in johannesburg and they said they will allocate the amount in my account and every week its the same problem my decoder it gets disconnected and writes that arears message,please assist me.