De-Activation of account

I have phoned on 1/9/2015 to de-activate a phone number. The lady has assisted me and said that she would send it to your department. She sent me the sms's with reference No. : *** on 2/9/2015. When I phone on 510/2015 I was told the contract still has not been de-activated and that I can only de-activate it on that day not a month before the time as I did. MTN assistant then had a look on the system, found the reference number and then sent to you AGAIN. I phoned on Monday, 19 October 2015 and AGAIN was told the contract still has not been de-activated. Phoned again today, 27/10/2015 and was told the account cannot be de-activated due to an amount of R0.87c outstanding on the account. They refuse to assist me regarding this and STILL charged me for the month of October even though it was supposed to be de-activated.