Samsung S7 set to update WIFI ONLY but use my data

I upgraded to the new S7 Saturday, and when I switched my phone on, it started updating without me knowing. I logged a query with 111, spoke to 'Vani' and he said it can be reversed,but I have to go back to the store and they must log a query. Went there and they just called 111 again and said they can't do anything, I knew I was buying a smart phone that does updates... I told them that my settings are set to update over Wifi only and they checked my phone and confirmed the settings were correct, but still my bill is climbing. On the first night it was R1000 and today on day three it is over R1200. It keeps climbing and I have logged 3 queries already, twice by dialing 111 and by going back to the store. I paid for the upgrade and will pay for the package monthly for 24 months, now i must pay hectic data bills as well just for switching on my new phone... THE SETTINGS ARE SET TO UPDATE VIA WIFI ONLY AND I PUT A DATA LIMIT IN PLACE, HOW CAN MY BILL KEEP CLIMBING? Vodacom is *****ing from me. <br> On top of everything else, I said to the store on Saturday I will take what ever colour they have in stock because I don't have time to go back, now had to go back. I just dont have time.