Bad service and incorrect billing on my upgrade contract

I upgraded my data contract beginning of October 2017to 10 gig every month for R199 pm with William from online upgrade sales . I received my bill this month to my surprise monthly subscription is R437 not R199 as agreed. On Friday the 24th I called Vodacom and spoke to Maxime and he updated on system and said William will call me before end of the day .Yesterday 26 th Nov I called Vodacom again spoke to Mpho from online upgrade she took my numbers and said Team Lead will contact me after I demanded to speak to someone in charge and her attitude was terrible as well. I haven't received a call from Vodacom to date. This is bad service from such a big company.