Vodacom cheats me

At the end of June I upgraded my Red Premium Plus package. I've been on this package for the past 4 years. I negotiated a deal and then happily received my new Samsung S20. I then used this package for the month of July. Then, suddenly, at the beginning of August, I suddenly find out I have no minutes and no data. Vodacom has, without my knowledge or consent, changed my contract to a Flexi 175 package. I've tried to resolve this issue but to no avail. I've spend hours on the phone already!