MTN. Very bad service

I have been having endless complications with MTN. Firstly I am trying to cancel my contract which expired in November last year. Secondly they have been debiting me since Januaury with an amount for a device which is unknown to me. I have been making numerous phone calls for the past two weeks to sort out this problem. They continuously apologize for all the incoveniens caused but cannot sort the problem out. They either drop the call or keep me on hold for up to 45 minutes. They are inefficient and have the ability to drive a person to suicide.This has been going on for the past two weeks. I also went to the branch in Woodmead and in Sandton. They are just as inefficient as the hopeless call centre. I am at my wits end. All I want is to have nothing to do with them ever again, bearing in mind my account is with them for over 20 years.Its a shame on them really.