MTN once again charging for GBs not used or requested

I have not used MTN and my contract was cancelled on 3 May 2022. It is impossible to have charges thereafter. I did not request prepaid. I did not buy 30GB once, twice or ever. This is extremely frustrating and annoying. The upgrade which I did not agree to has been reversed as per request. Reversal summary: The main action is taken: Upgrade reversal MSISDN:*** Order number:*** Reference Number: *** The problem is that I still received an invoice for days/usage to the value of over a thousand rand AFTER the cancellation when I didn't have access to MTN network. Pls adjust my account to zero Rands and resend the correct invoice. I have had 3 confirmations that the upgrade is reversed but no confirmation that I cancelled MTN and have no desire to do "Pay as you go". I'm being charged for GBs that I have not ordered, bought or used. This is extremely frustrating as it has been months of correspondence and I just want somebody that is able to fix this to do so. I am pleading with you to help me. My Mom passed away, I had to find a place to stay, I can't afford the internet. How much longer is this going to go on?