incorrect billing which lead to blacklisting

I upgraded my vodacom contract from a 3gb which i was paying 169 for over 10 years to 10gb which was supposed to be 199. I then get billed 499 for the 1st 2 months until vodacom picked up the problem and rectified it to 199 after numerous debit order reversals. I then find out that I am being blacklisted due to my account going into arrears because of the 1st 2 months 499 debit orders that i reversed, regardless of me making the correct payment amounts thereafter under instruction of vodacom. This is absolutely pathetic service. I am about to take my 10 years worth of business elsewhere and sign up with a different service provider. I would like to be contacted as soon as possible by someone who has senior authority at vodacom and im not talking about customer care, accounts, billing or cancellations - **********