Incorrect billing

On the 11th of December, I contacted Vodacom and requested to cancel my contract( pay off), was sent to cancellations department and explained.that due to me being unemployed, I would like to pay off and have my services cancelled, I was telephonically given an amount to settle.

Three months down the line, I receive a message that I am on arrears, I contacted billing about a week ago, was transferred to retention department, the gentleman tells me that it was their error, then he says that he will have to suspend my line to convert me back to prepaid and I will lose all data and airtime and I said if I will be credited, ts fine, then he said Ts not possible, then I asked him to schedule the cancellation for the week of the 16 in April, whilst busy helping me, the line cuts, then earlier this week, I receive an email reminding me of what I have to pay to Vodacom, I am ****ed at the level of service at Vodacom....

I do not owe Vodacom and I'm gonna go crazy should they terminate my line for their own mistake