I'd be willing to bet you'll have to continue paying data on those lines for the duration of the contract.. $30 x 24 months = $720, plus the $200 you spent on the phone in the first place, means you're making a bad financial decision..
Well one line already has data on it so no extra charge there. Also it has always been my experience that you can change features on your plan online at no charge, can't imagine this would change. And even if so there is a 14 day return policy.