Vodacom has failed me as their customer.

I have 24 months contract with vodacom which started July 2018, which must be due July 2020 but it seems like I will pay forever since they keep on saying I did upgrade on my contract which I never did. I tried calling vodacom and I never get helped because the upgrade is still appearing on my profile. I want to settle my contract with them but due to this upgrade which I never agreed on am failing.