incorrect billingfailure to rectify

i have been incorrectly billed from dstv. i have rectified the incorrect amount that was billed to me.i am now being disconected regularly due to the mistake not being rectified on dstv systems.i made calls to the center were i have been told by advisor's that they will rectify my account. i seem to begetting no joy in the service as i am a customer for more than 10 years with dstv. i asked for the call center supervisors to assist me but still have not received a call, all calls are recorded make available the recordings as i am totally not happy at all with this poor service and poor quality of advisors who fail to assist me. my account is debited monthly without any problems. but i now feel i am paying for poor services. please can i have some action from management on regards to this complaint. i was told to be contacted today the 05/01/2016 from the supervisor as he was on a call during the time i made contact. it is now 18:20pm and still no call received. is this acceptable??? easy to pay but fraustrating for customer services.