Deducting more money than what I signed up for

I visited MTN shop 20 March and spoke to MTN customer service after I have been there for 3 Fridays to resolve my problem.In the end I opted to downgrade 1 of my no's to get some sort of closure on the 2year problem I have with MTN.Monique from MTN confirmed that 1 no was cancelled with immediate effect and that the downgrade for the other 1 was sent through.She also confirmed that there would be no more deductions for the old contracts for which I never signed contracts.Only the new contract I signed on 13 March 2015 would reflect for payment.The reference number for this case is ***.<br> To my dismay MTN deducted R619.00 from my account 1 April.This is far more that the R149.00 contract I signed up for and even more than what they previously ********ly deducted.Then I got an SMS to say I have been credited with 600MB Data, 100 Minutes and 400 SMS.The only correct information is the one for the 100 Airtime minutes-is this perhaps why I pay so much for the service?And I receive messages to say thank you for purchasing Internet bundles WHICH I DIDN'T DO.I am not going to spend another 3 days to sort this out.I want MTN to correct the information and pay back my money immediately