Vodacom incorrect billing 3 mounts, still no help

Vodacom is billing me incorrect for the past 3 months and for mounts I am struggling to get any decent help to resolve this issue. I am spending hours of time explaining and logging disputes and at the end they never come back to me and I end-up paying the incorrect bill, just to have my lines opened. After I have to find out from Vodacom, who have offer me this package to upgrade to, I confirmed from the Vodacom approved seller, that Vodacom should have all the details on their system and that should not have been billed as Vodacom have billed me from September. So why can’t Vodacom see on other Vodacom departments what is happening and try to help a long standing customer to resolve the issue of their own mistakes somewhere down the line. Now a customer have to spend hours of time try to resolve it for them. I need someone from Vodacom to resolve this issue, as I have decided not to pay for all of my Vodacom accounts until this issue have been resolved. If Vodacom can’t keep to their contracts, how must I keep to mine and how on earth will I be able to cancel all my contracts if this is not resolved soon. I have tried and wasted 3 months of my time. A long standing disappointed Vodacom customer!