Back-dated bill for product I have never had

After numerous requests for help with an incorrect bill (I am getting a back-dated bill for a product I never had and I continue to be billed , after moving cities, for the same product which I did not order AND DO NOT HAVE AT PRESENT TIME EITHER!) - The product in question DSL 20meg line. All I have ever had and still have is a 4meg ADSL! I have made call after call! Sent e-mail after e-mail!!<br> I have still received no assistance and my account has not been corrected. Close to two months later and still no assistance. Tel number in question: ***. Who should I contact next or is my only resort ICASA? Please advise.