Vodacom Blacklists people for fun

For the last year I have been trying to sort out this issue. Vodacom has repeatedly been non responsive to helping me sort out my account. I had a tablet contract with them which expired last year. The year before my banking details changed and I went into a store and changed the details myself. 6 months later I was handed over due to non payment. Imagine my surprise when I was eventually notified of this. I was not called, messaged or emailed to notify me of any issue on my account until the account was almost R1000. I was unaware of this issue because the debit order was moved to my husband's account and neither of us noticed it never went off. So as of November 2018 I paid the outstanding on the account and requested an upgrade as the contract was at its end. I was shunted around from accounts to services departments for 3 days only to be told I could not upgrade for three months. Fine I then requested to end this contract as it was already at its end and I could not wait the 3 months to get a tablet as I required it for work. I made an alternative plan. I was then told I may not cancel the account and that was it. I told them they could then keep their account and ended our conversation. To my knowledge my account is and was paid in full. My contract has ended, but when an itc check was done I found a lovely surprise that Vodacom has now blacklisted me as a default payer. I have not had any communication from them since November/December, so I would like an explanation!!!