deactivate seemed to work on another phone
I had the same reboot loop problem on another Verizon phone (an old Nokia). Resets didn't work, the Verizon store couldn't help and told me I needed a new phone. I bought a new one on ebay and switched my account over to the new phone, deactivating the old one. Well guess what: a few days later I idly turned on the old phone and it no longer had the reboot loop problem. I did not try switching the activation back to the original phone, but I'm wondering whether if I had just deactivated and reactivated the phone, it would have fixed the problem...