MTN Contract

My contracted ended last year. I was offered a new data sim contract. I never received the sim card, but MTN was deducting money from my account. I reversed the money and send them an email. They never responded but keep on deducting money from my account which I reversed. Now they have handed the account over to attorneys. The attorneys are sending sms's everyday. I phoned MTN Legal and the consultant advise me to write a sworn statement and send a certified copy of my id. Nothing happened, still receiving threatening messages from the attorneys . Phoning MTN Legal and you are on hold for 8 minutes, speaking to a consult whom then cut your call