Sick of Vodacom Employees mistakes costing me!!!!

I received a call from a Vodacom Salesperson, who advised me to migrate to a different package... after double checking what she was offering, and asking to make sure AGAIN.... she convinced me that the TOTAL amount at the end of the month would be R 1600.00..... Debit order last night: R 2700.00!!!!! Phoned Customer Care, found out that I got the wrong advice from Vodacom's sales lady. To undo the migration.... ANOTHER R2000?!?!?!?!?!?!?!?!? How can Vodacom treat their customers this way? I TRUSTED the advice given to me by Vodacom, now the problem is mine, and it is a VERY BIG MESS!!! EDUCATE STAFF THAT HAS TO DEAL WITH THE PUBLIC/CUSTOMERS!!! What do I do now? They have access to all my details, and calls are being recorded..... surely someone could help me? No.....when I phoned Sales department I was put on hold TWICE today.