Over Charged for Cellphone Insurance

I was overcharged R129 as supposed to R85 per month from Dec 2014 - Jun 2015. I have called numerous times to have this resolved and I keep on getting empty promises of a refund with no feedback form people that has assisted me (Felicity May, Sylvia ***ley). I was promised the funds month end Jul 2015. I spoke to a consultant 12 Aug 2015 who promised to call me back but it's been 2 days with no response. I called Sina Mokatse today who tried to assist but she couldn't pick up anything on the system of a refund nor that I was overcharged. I have been very patient but there is so much that one can take. Please Assist me URGENTLY with this.