Struggling to cancel my contract with MTN

I have been struggling with the Lte router I bought via online through MTN. The problem started when I changed my banking account and updated them in time, but the disconnected me for a whole month and I still paid for the service up to date. I opted to cancel the contract was sent from pillar to post until I was told to return the router to the nearest store. I did that on the 31/05/2024. The store gave me a reference and I immediately called the call center and they told me they can’t assist me because I did not buy it from them, and its so funny because the bill comes from MTN but no one wants to help me. I even sent emails to the complaints address and no one is responding.

Today I called Rewards Co because I saw their name on the POD, the lady helping took the Ref number : IRMS***5 and told it will take 21 days for cancellation to be completed, I asked for a reference to my call to make a follow up and she was not helpful she even hanged up the phone before we conclude. I guess she was in a hurry to knock off because immediately when I called back it took me to voicemail that out of office hours.

I really need urgent assistance, I know they will try to debit me again and I haven’t used that service since April.