Mtn contract

I got a call from one of the consultant at MTN telling me about the upgrade on my MTN contract, she verbalised that instead of paying R165, which I normally pay every month, MTN is offering R106 every month, which was a great deal and I accepted, as soon as I hung up my phone, I get an SMS from my bank notifying me of a debit check of R600 and something which I was not told about over the phone, I then got a contract through my email address, I called MTN and I was told to ignore that amount....ignore it????? After it went into my personal space I should ignore it,why send me the contract and why go into my bank space for a debit check if I should ignore it? Why didn't the consultant not mention that 600 something amount to me???? That to me is ***** at its best, I need an explanation.....