Settled account

This people is harassing me since last year, my cell c account has been settled with them, last year Oct already, they say they can't see payments, I sent through proof, no response, this year Jan they start again, I start to pay again, still they don't see, is this their ammo to rip people off maybe. The service is really bad, u ask for superior, ur call get disconnected, they can't answer the call get disconnected. I'm not any further payments, until I hear from higher authority.