Vodacom invoice wrong & not getting back to me

Long story short, I did an upgrade over the phone. Then got an invoice that was totally different than what was agreed upon. Called again, they said "No it will change, just be patient". Never changed. Called 3 times after that. Never got someone to fix it. Last time I was told that I would receive feedback before 21 March. I asked "Promise"?, since I've been let down so many times. He said yes, promise. Haven't heard a thing back yet. Super disappointed. I really hoped that this time would be different.