Incorrect Billing

I have called 808 and they told me the 12 month promotion has ended however I upgraded at the Canal walk branch and the contract I entered into stated after 12 months the data bundles would be removed and the contract remained R349. The person I spoke to on 808 said I had to call to cancel the bundles I was not told about this. she cancelled the bundles from September onwards making them R349 but July and August needs to me sorted out as Im not prepared to pay this amount when it was a mistake on MTN part. the person at 808 said I must take my contract to the branch. Please can someone request the contract from canal walk as I do not have time to go to the branch and rectify the billing error before my debit order goes off, this is a inconvenience to me. I have had constant problems with MTN in the past where I had to run back and forth to the store to resolve. I have been a loyal customer for years but yet I keep having problems.