the phone doesnt read the battery. so either the internals are broken or the battery.
This link will take you to Moto's Service & Repair page. It has some pricing info as well.
Another option is to compare it with buying a used phone on ebay or craig's list and then selling your phone for parts. If you do that, the best way to make sure the ESN is clear (not stolen or associated with an unpaid contract) is to take it to the Verizon dealer with the seller and have them check it before you buy. But you can also check online here if that's not an option.