Over charged

On Feb 15, I was contacted by Manele (Consultant) offering me an upgrade on my contract *** which expires in Apr/May 2015. She told me that I will be paying R370 and on the current contract I am paying R592 for 2 devices. The contract wil be for 27 months and the migration will be done after three months, so for the next 3 months I will be paying about R410 because I am canceling the other contract and afterwards I will be paying R370 on the new contract. In March before the 15th I notice changes on my account and I contacted the Customer service several time and I was told the migration was done earlier on the system but for April I will be billed R370. To my surprise the bill came for R962, I contacted customer service (Norma consultant) told me its for both devices but the query will be forwarded to her seniors they will contact me to explain. I told her that I am going to reverse the debit order because I did not budget for that money and I will pay R370 as I was told. I contacted them several time but they never came back to me with answers. Now my account is suspended.