Vodacom 4u clearwater

I recently took out a contract with vodacom,which states that I should be charged R375 and for the past few months I have been charged a lot more ! I have been trying to reach them for 3 weeks now and I've went into the store as well to fix THEIR fault but they keep ignoring me and they just say that they can't help me..so i called vodacom customer care and the consultants answer is i have to sort it out with the store What do I do from here because their service is so poor and nobody is willing to help.