Billed for content servuces I didn't sign up for

In March 2015 I signed a 24 month contract at vodacom for a tablet that cost R110 per month. The tablet was only to use to receive email, read e-books and browsing on the internet. But when the first month's bill arrived I was billed for a staggering amount of R494.90 and so it continued in May I was billed R359.41 and in June received one for R317.90. Unable to make it to the Vodacom shop until this Sunday. When I got their I explained to the employee what was going on he went onto the computer but found nothing he also called someone but they couldn't tell him what was wrong. When he was done he told that there was something called content services activated on my tablet by me through sms and just in general told me that it was my fault that my bills were so high, but he also couldn't explain what the content services were. He then cancelled the content services and told me that that's it but on Saturday my account according to the vodacom app was R188 and today it changed to R215 and furthermore how can I activate anything by sms if my tablet can't even send or receive any sms's. I'm appalled by this service and can say that I will never take out another vodacom contract.