Incorrect Number Upgraded - Unhelpful Consultants

I recently (3 weeks ago) contacted MTN's Sales/Retentions team through their 135 contact number to upgrade my data line/number. The consultant that took my call assisted me and verified the number that I wanted to upgrade (or so I thought). Two days later I received an email confirming my upgrade, which is generic welcome pack dated April 2021, and I also received communication on when my device (router) would be delivered. I received the router device as communicated but a day or so later I then received an SMS on another number of mine that my plan was successfully changed. However I had not requested that number's plan to be changed. Upon further investigation I found that, the upgrade was actually done to another number instead of my data line. The number that was now upgraded was a new number so it could definitely not be eligible for an upgrade. So how they managed that still beats me. I have contacted their contact center several times in the past two weeks and the one guy who actually took my call (Kwanele - 19/08/2021) , has since promised to get back to me and I am still waiting. I have sent an email too but till this day have no response. A lady called me today but was unhelpful as she says she cant access the account, the person that opened the upgrades needs to assist. But still no-one is contacting me. I refuse to be stuck with an upgrade/plan and the costs included, that I didn't request for or approve. I have been contacting the call center well within my time for this to be corrected (I was told I have 10 days to cancel/change a plan after it was implemented, even though this error isn't my fault).

For a person that has 5 contracts with MTN and has been a client for well over 12 years, I am extremely annoyed at their customer service.