Vodacom has the worst customer service I've encountered!

My contract is expiring. I try to do the upgrade online but get a message that I can't do this online for my number. I call the upgrade department and the can't find me on their system. I tell them I'm on the old system - I know this from previous attempts to get something done via the call centre (and I've repeatedly requested to be moved to the new system for years but nothing happens). Due to being on the old system the upgrades dept can't help, I have to call the cancellation dept. Eventually I get to someone who can help and sets up the upgrade on 13 Jan and I get told that the new contract will be in place from 1 Feb. Come Feb and nothing happens, still on the old contract. Big mission trying to get through to someone to follow up - they dig into it and say they'll call me back - no one calls back. I call again the next day but asking for the same person proves useless so the new guy says he'll help me. He tries and then says he'll call me back. I say that Vodacom people never call back but he promises he'll call back. I ask what I should do if he doesn't call back so he gives me another number to call but promises to call back. He doesn't call back either. I now call the number he gave me and they tell me they can't help me and that I need to call the upgrades dept! Useless! But I expected this as it happens every single time I need to upgrade. But my contract is due to expire and then I'll get charged more without any additional benefit. How the f@#* is one supposed to get anything done with a company that clearly does not care about its customers.