Horrible service

MTN South Africa your service is horrible and ***********,inconsistent staff from your call consultants I was offered a cellphone contract but I received a sim card which I never activated and refused called numerous times to decline it and you stopped deducting because I had informed you I do not need it yet you are ruining my credit score because it appears as an unpaid account, why would you do that. I do not want your or sim card since October and you always tell me you are looking into it.