I'm going through a similar issue. Instead of a $200 rebate, I tried to get them to honor their 14 day price guarantee policy when they dropped prices. Canceled my phone order, was going to reorder online at the lower price, they conveniently had issues on their side with processing the cancellation, so I couldn't reorder the phones that day at the lower rate (Cyber Monday). I've been trying to get them to fix it ever since Cyber Monday and have been in contact with no less than ten different Verizon reps. None of which follow up after publicly replying to my posts and sending an initially private message.
You're best option is to file a complaint with the Better Business Bureau and hope that forces Verizon's hand.