When you click on the rebate center link you will be redirected to a page that asks for the promo code (which was sent in an email) along with your purchase date (this means date of device port or date of device purchased if buying from verizon). This has to be done within 30 days of your activation date! You will receive a confirmation email that has a tracking number for the MasterCard $250 that Verizon send. In that email it also states that it will take up to 8 weeks to receive.
Hope all of this information helps you & anyone else who had concerns about this promotion. I called Verizon for help with registration & that is how I found out that it is actually a legit offer, not a scam. I spoke with a LIVE Verizon Agent not online chat, etc.
However, I don't know if the offer would still be available at this point because I see your question was posted back in June. Here it is Oct. I recently switch to Verizon & tonight I, too, had concerns of whether or not the offer was a scam or not. The stipulation of the promotion is that your service has to remain active for a certain amount of time without being disconnect or the $250 will be taken out of your payment option/you will have to pay the amount back.
Good luck!
Rebecca