You need to call Verizon and report your phone as lost (if nothing else, to prevent somebody else from finding your phone, fixing it, and running up your bill or doing something illegal). I might be wrong, but if you had insurance, I *think* it might cover loss or theft, so you'd probably have to pay a deductible (it used to be something like $50), and they'll send you a new one. But you need to call them as soon as possible, and see what they say.
geocritter is correct, if you've got insurance, you should be able to report is lost. you will have to pay a deductible for it, but you'll get a new device/battery. which is much better than having to pay full retail price for a new device.