MTN contract issue

After having read the reviews about how MTN is a bad service provider, I still went ahead and opened up a contract with them. Stupid of me I guess.

I opened up a contract with fixed LTE sim only and I was not advised that this required a special router to work. This meant the sim only deal was useless to me so I cancelled it within the timeframe stipulated by MTN 7 days. I then opened a contract for R499 Uncapped fixed LTE. This came with a router and is working perfectly fine.

On the 18th of January 2022, I received two invoices totalling 749. I immediately contacted MTN to query this and I was advised that there is an error on the invoice and the billing department needs to check and advise since it's my first month and the billing was finalised on the 17th it is too late for the 22nd debit order date. This will therefore be debited end of February. To my surprise, the 749 went off my account on 22 January 2022. I immediately contacted MTN again to query this. With many failed attempts and numerous ticket numbers. It is still resolved.

I was charged a 150 for December 2021 I do not know why. I was charged a pro-rata amount of R88 as my new contract was activated on the 11th of Jan. I was then charged 499 which is a full month subscription. This essentially means I have prepaid for February meaning at the end of Feb I am going to prepay for March. Can someone please explain this to me?