Cancellation date can not be confirmed and neither can final installment date

I cancelled my contract in December and was advised that the contract will be cancelled on 6 February, where after it will take 24-48 hours for my number to be cancelled from a contract sim to a prepaid number. I called on the 4th of February to confirm if the cancellation was in order. I was advised that the contract will be cancelled on the 6th. I called on 10th to advise that the contract has still not been cancelled. I was advised that it will happen but they not sure when as they are waiting on MTN to do the necessaries. I was also advised that they are not sure whether or not I will be billed for an extra month as the cancellation did not take place yet. But if I am billed it will only be for "1 month more". Today I have received the data bundle and probably will be charged. So what is the point of cancelling 30 days before.