Vodacom Not Helping

I have been trying to resolve a billing issue with my service provider witch is Vodacom SA from end of December 2014 for data usage on my account at R2 per mb resulting in my account being overcharged by nearly R3000.00.<br> I honestly spent hours on the phone talking to customer care and team leaders and technical departments and the \ back office "and Accounts department trying to resolve the issue from the 3 rd Jan 2015 when they said invoices are generated"