Unknown subscription

I have a data contract with cell C for which I pay R249 per month for 20Gigs of data(10 daily and 10 midnight).I hardly finish the given data per month but my bill started going high from September and when I contacted Cell C they told me I am subscribed to basebone Hulkmobile Uchater,I don't remember doing any subscription and the cell C sim card is in a modem so I never directly do anything else on the sim except to connect on the internet using me. Last month they billed me R450 for the subscription and now they are going to deduct R750. I couldn't get any help from Cell C as they referred me to basebone and I am not able to get help. I am now paying for a subscription that I never joined and Cell C has failed to help.