Don't upgrade with Vodacom!

Vodacom retentions and upgrades department have no idea what they're doing. I did an upgrade on the 27th of November for a Samsung Z flip. There was a deal made for me to match another deal from a different service provider so that vodacom could retain me. The deal offered was to be effective as of 1 Dec. Now when I look at the bill and invoice they have charged me for the previous package and new package. I have called and complained several times with promise for it being escalated and now they are charging me twice for the new package. This is not the first time I have had an issue with upgrades. Vodacom staff just don't know what they're doing!!!