Fonechoice is eating my cash afta settling account

My contract period is 25-09-2013 to 30-09-2015. Today and other previous months I have been paying fonechoice R269.02 (debit orders) I called in and the consultant by the name Leven Valentine(hope it is a correct name) confirmed that indeed fonechoice have been overbilling me by three months or so. She told the system error story which was farfetched and initially she laid a guilt trip that I never made a payment from the beginning of the contract to the 26 November 2013 - LOL, why didn't they raise an alarm then? Think I am stupid? I want my refunds as soon as yesterday. i had a bad experience with Fonechoice, so they should not think we are tied up now. I demand what is mine so as to run as far away from them.Call me with the evidence of my payments and explain why this happened. I demand the truth. NOW!