Taking long to cancel my contract

21 days before my contract ended I went to a branch in pretoria to cancel my contract. At the branch they stated that I can phone 808 on the 3rd of may then the callcentre will cancel my contract and move it to prepaid the same day.<br> so when I called the callcentre(ref ***), they say they will phone me back, up and till today no one have phoned me! I would like them to cancel it asap. My debit order is suppose to go of at the 12th, so I dont want them to take the money from my account as I already took up an better offer from another service provider! <br> I cant believe it is taking so long, as the contracted ended I dont have any obligation to mtn!!!!!