[mrlmd1]

This has been an ongoing problem addressed before in numerous threads.
It's probably the battery, but not really the battery, it's the dealer who installed it.

First off, hook up a good battery or jump it with cables from a car battery, WITHOUT THE CAR ENGINE RUNNING! You don't want to fry the GZ's electricals with the output from a car alternator, but the battery is just fine to start the bike. Don't forget, + to +, - to - on the cables.
If it starts, that identifies the problem.
The batteries for these bikes are usually AGM sealed batteries and they MUST be fully charged up first on a charger after being filled with acid before initial use or they will NEVER hold a full charge to start the bike more than a few times, then they crap out, have to be charged again, and will start the bike once or twice, then die again. If the dealer did not charge the battery for a few hours at least before installing it, it's already ruined and you need a new one. You (the dealer) test it by putting on a load tester and you will see immediately if it's any good. Make him do that and give you a new battery.
If you get the bike running, you can easily measure the voltage across the battery terminals to see if the bike is charging or not, and I would bet this is fine.

I bet you anything the problem is the battery, don't start looking for exotic problems on a new bike with only 300 miles. Get a new battery, charge it and your problem is solved.