It never ends....

I have been trying to cancel a contract for more than 5 years. It's only R45 per month. But I've sent numerous emails, I've contacted them, I've gone to the Vodacom shop, but I am not able. I've send so many email to ***. I've spoken to your agents, and every time they promised the line will be cancelled, but still it has not happened. I took out this contract many years ago. After the 2 years initial contract period I phoned to cancel. Then they told me someone at their Randburg shop (i am from Pretoria) upgraded the contract. I explained it was not me, then they would do investigation. Then from there the contract is still running. I don't know what to do. If I cancel it at the bank, I am charged, and then after 3 months, the debit order goes on and recovers the 3 months I've stopped it. I am so frustrated. How do I get to stop this contract. I don't have a sim, and have not used this from many many years ago. Then apart from terminating this contract how do I get my money back?