Breach of Contract

I have a contract phone with MTN for some years now and I keep on paying weekly for caller Tunez which I did not subscribe to.This is very unprofessional of MTN I have tried every avenue to have this cancelled to no avail am now writing here on Hellopeter to see if this will be cancelled off my phone otherwise I will terminate my contract with MTN since this is not part of what I signed with MTN.