MTN NO OPTION TO CHANGE FROM CONTRACT TO PREPAID NO WAY TO PHONE MTN

No option to change from a contract to prepaid after 2 years. I have been to a MTN store on 21 September with a request to change the contract to prepaid. They 'canceled' the contract and said MTN will phone me to confirm. Nothing happened. I have Send 6 different e-mails reference no *** and phoned today for the 10th time without any help. MTN deducted another R1800 from my bank account without my consent (after the 2 year contract came to an end).THERE IS NO OPTION TO SPEAK TO A CONSULTANT 083135 I HAVE BEEN WITH MTN FOR MORE THAN 10 YEARS