Vodacom data packages an absolute *******!

I have had a contract for years for two mobile phones, and a wifi data package. My data on my phone is suddenly running out at an alarming rate, and I inadvertently accepted an automatic update costing R115 every time my data runs out. This now happens almost daily and sometimes more than once daily! Its ****************! When I try to have it cancelled I get told to dial the 082 135 number, but I get nowhere with it. Secondly I had a 10 GB data package on my WiFi which would run out on average a few days before the end of the month. For the last few months it runs out a day or two after the first day of the month, and Vodacom cannot tell me why!