Incompetence

I was called by Vodacom upgrades and offered a deal consisting of the iPhone X, R350 airtime and a black Friday deal of 5gb data for 24 months at R1069pm, for everything mentioned, for doing the upgrade with them at that moment in time. I checked my bill so far and it says I owe them R2388.50. They are charging me an extra R999 for a 20gb data package I didn't ask for, but was told that it's a promotion they offer when you upgrade. The 5gb of data was added for December, which I'm suppose to get monthly, is also no longer being added to my account as of 1 January . I have phoned repeatedly over the last 6 weeks and keep getting told that they will rectify, it's an account error on their side or its been fixed so I shouldn't worry, and I'll receive an SMS with confirmation of what was said and a reference number. The SMS never comes.