Unhappy customer

I have been a loyal customer to MTN for Years i was happy until recently. I Paid of my account in November and i called in for my services to be changed from contract to prepaid. my account was on a zero balance now am told that the services was still active and am billed for it. I was told that my account is handed to Lawyers. i asked them to listen to the recordings and am still waiting. I have called in so many times and nothing gets resolved. Why they hiring people who cant do the job. I paid off my contract. Ever day you call and you are told different things