Unable to get through and double charged on bill

I have contacted MTN 3 months ago as my contract expired, I wanted to remove the promotional aspect of my contract so that I would be paying less to save money as well as keep my contract active until I am ready to upgrade. I was advised that it will take up to 14 days to remove this from my contract and I will be charged R288 per month thereafter. <br> <br> Upon receiving my bill for the next month, I noticed I was charged full and not the confirmed reduction in the previous month. I called MTN again and was advised that the process has not been completed as yet (OVER 14 DAYS!!) and I will be credited for this on my next (April 2015) bill. <br> <br> I have received the April 2015 bill and not to my surprise, I was charged R498! No credit was processed either. I have been trying for 3 days now to get through to the call center only to have the call automatically cut after every 3-4 minutes. <br> <br> This is unacceptable and appalling service! I want a refund for the recent bill and I will also appreciate a call since I cannot get through. If this does not get resolved, I will be taking the matter much further with my complaint and I will cancel my contract.