Billing

I called in MTN numerous times and was told I can only cancel my contract on 09/12/2021. This information was wrong because they agent I spoke to today said I can cancel my contract now. For my invoice for 12th November it showed amount due was R99 on 01/12/2021. When I check the app again they changed the due date to 01/01/2022 and from paying R99 in December, they want me to pay R1000. MTN services are pathetic.