Poor service

Upgraded from a Black Barry phone to a Voda 3g tablet on my existing contract R89 (1gig) a month and took out a new contract - same 3g tablet for R59 (500mb). On the box of the tablet it states that you receive 200mb data for the 1st 12 months. It do not state that it is only for cash purchasers. When i queried Vodacom about it they did add this 200 mb to my new contract now receiving 700mb but refuse to do so on my existing. Stating that it is not included in the contract. But it was not included in my new contract ????? They are investigating the old 1 for almost 2 months. Every time a send a mail for progress they say its been revered. I will never upgrade with Vodacom again.