Vodacom Not sticking to their contractual obligations!

I went to Vodacom to upgrade my phone. I made it clear to them that I only needed the phone and airtime and that I have a mobile wi-fi device that I use for data. They agreed and it actually worked out to a little less in airtime. Only 50minues, but I was okay with that. They said they would also upgrade my wi-fi contract because I was paying TOO much for data and they were running a special.. more data for less money! GREAT! I have a bill for over R100 more, after I paid them IN-STORE extra money for the new phone to be initiated. I have NOT received my AIRTIME, and I am NOT receiving invoices, after I have repeatedly asked them to E-MAIL ME THEIR INVOICES.. Only way I can see what I am being billed is by going onto their Vodapay app and kinda view it there. AND IT SAYS I owe them over R600 when I as previously paying R473 only. They refuse to reply and just ask for an laternative number to call me on!??? Riciculous. I have seen SO MANY BILLING COMPLAINTS on their site.. it sickens me!