Expired contract but still debited

I have been a loyal customer for Vodacom for over 15 years and am very dissapointed at how they’ve handled my request’s lately. I took a contract with them in 2021 and realised sometime last year that they had made a mistake whilst capturing, instead of capturing 24 months they capture 36 months. I have been trying to get this sorted out since last year already. They acknowledge the mistake everyone when l call as they can see my contract but sadly no one is seems to be doing something about it except the ongoing apologies. I am paying a lot of money for an l-phone contract that should have been finished a month ago and even this month, it’s clear that l will still be debited. This is very sad indeed, l had complained so many times, l do not know what to do anymore! My request get closed unattended and no one even bothers to call back and explain why this query is closed without being attended to. I am so disgusted by the service, they just don’t care!