Wrong Billing

I upgraded my contract to 24mnth Mtn Anytime 200 Top Up on 16th October 2015 which was supposed to be billed for R539 monthy, but my total bill has come up to R758.73, infact more than that in the December invoice. I went to query this at the Howick, KZN store and was told that i have 2gigs data bundles billed to my account that charges me R214.91, which NEVER comes through phone coz i buy my OWN data bundles monthly on the 20th. They didn't know how to help me, so they logged a query for me with *** and nothing ever happened. Than i called the 808 line to query the charge myself and the lady who helped me also told me same thing. There's a 2gigs data bundle that I'm ****ing paying for but it does NOT appear on my history statement meaning I'm NOT really receiving it. This lady also couldn't help me and told me that she will log my case with the billing department and gave me ***. And again no one ever got back to me. And end of the month of January, my bill again came up to R758.73. So basically I'm paying for a service that i did not request for and not receiving. I don't want this 2gigs data bundles. IT'S BEEN 3MONTHS NOW AND NO ONE HAS BEEN ABLE TO HELP ME!!!