MTN Horrible Service and now Threaten with Blacklisting me

What a terrible service from MTN Retention (Horrible) Department.

I struggled for almost a month to get my contract cancellation processed after I returned the device within 7 days. I was told I had to be assisted by the same person who was assisting with the upgrade. It was finally done by someone else after several attempt to get that person to assist and even when my call was escalated to the department supervisors I was still not assisted.

I returned and cancelled the upgrade within 7 days as advised there will be no charge if I do so, but end of October 2020 +R5800 was debited from my account. When I asked I was told it was for early cancellation of a contract. They fixed their error when I mentioned that I was told there will be no charge if I return a device within 7 days - someone didn't do their job. End of November a new debit of +R900 was also debited, still no explanation what was it for. I tried calling and sending email which were all escalated to the horrible department and no one called back as I was advised they will call back.

On Sunday, 06th of November 2020 I received a final notice on my emails saying I'll be blacklisted if I don't pay the R931,33 within 14 days. I payed the amount as I care about my credit history (MTN doesn't care). I logged another call with MTN call center again and was told will be contacted within 48 - 72 hours - which I know it will never happen, but I will be blacklisted if I don't pay.

I emailed them the long list of reference numbers I kept getting via SMS of cases being opened and closed