48 month vodacom contract

Dear Vodacom, Yesterday I made contact with your call centre. As previously requested I want to buy out the contracta and terminate our relationship. I then discovered with the call centre agent that my contract upgraded early 2018. When I queried the date of the next upgrade I was sent a message and the call centre agent confirmed that I can only upgrade in October 2021 and the contract will end in January 2022. Taking this into account it means that I have a 48 month contract. Since when do you offer 48 month contracts on handsets? I never agreed to a contract more than 24 months. Also I have now over paid for 8 months on a handset that has been paid off since January 2020. Will this mean that you will reimburse me with the money over paid?