Unhappy Cell C customer

I have one cellphone contract with this pathetic company since January 2014. I realised early this year that they were charging me for two contracts, then I called in to report this *****. I was asked to send an ID copy and a Sworn Affidavit which I did on 04/03/2015. I received an email from them on 23/03/2015 saying that their system shows that I've only received one phone and the other contract will be cancelled and later that day J Lekalakala from customer service called me telling me that he's cancelling the other contract and I'll be refunded my R3 500 in 7 to 14 working days. It's now almost 2 months and I didn't receive my money as promised. I call them almost every 2 to 3 days for feedback and they are sending me from pillar to post. Everytime I call they keep lying to me that I'll be contacted in two working days and even today I have never been contacted. I regret changing from MTN to this usless company.