Talking to a brick wall

I have asked telkom over and over again, speaking to customer care a number of times, emailing Telkom requesting itemised billing be emailed to me in order for me to check my calls made. They will keep sending me an invoice for X amount. Am I talking to a brick wall at Telkom? Secondly this new cordless phone from Telkom is useless. A number of times my calls are cut of and other times when one does answer the phone the caller cannot hear a person answering. This roaming on MTN is useless. Why does Telkom not have its own towers? Please will Telkom reply to my complaint.