Unauthorised debit orders

What seemed to be a great deal, has turned into a nightmare. I bought a Vodacom Smart Tab 3Gthrough Elite Mobile that was on promotion for R79.00 per month. The telemarketers have contacted me afterwards promoting different apps and services. Being polite, I would listen and then decline the offer always stating that I cannot afford more than the R79.00 They will then assure me that I will only have to pay extra if I activate or access the service. I have not activated any service - in fact I ignore the e-males. I have not authorised any debit orders or agreed to terms and conditions. They have been payments going off my bank account to the amount of R526.00 for the month of April! I did not even get sms alerts from the bank, with the result that some of my other debit orders could not go through. For something called Hotspotter there has been three deductions. I have e-mailed their support services twice, with no response.