Over billed

I took up a contract on the 28th of December and the consultant informed me I was gonna be pro -ratted and first month which was Jan I was charged R1149 if not more with some change and I has asked for the 1GB contract which is R600 and second month the same thing happened and we on the 3rd month and I'm being charged R1,998.94 this month which is March. I called the call Centre in Jan and they said its capped to what I asked co the first consultant didn't cap and now I'm paying more than I agreed on from the first day. I'm so unhappy , angry and disappointed in their service .