Cancellation of Cellphone Insurance

I have been trying to cancel my cell phone insurance with MTN since the upgrade at the end of July. I have tried to use the MTN insurance number every time I dialled the number I got cut. I decided to use their MTN SA service twitter account with out success on the cell number as the insurance has never been cancelled, although they managed to cancel the other number. They sent me an email confirming the cancellation on both numbers in September but to my surprise nothing has happened on the number I'm using . I have sent the email back to them explaining the problem and in October one lady phoned and I explained the problem to her she said she was going to resolve it. To date I am still charged the insurance by MTN on the number I have mentioned above I have even sent an email again they are just not responding. I will appreciate if hello peter can intervene I understand MTN does like clients like me, these are some of the reason why are I don't want they insurance because some time last year I tried to report about the phone I have problem with they have never even called me. When I upgraded I was told to contact insurance dept. to get insurance of which I have never did