So if that's the case, could I jump it off with either a car battery or one of those jump boxes and if it starts off that then I would know.
Yes you can, If it starts run it for a while, Then get a battery tender, [float charger] and let it charge over night.
If it still doesn't hold a charge, It's new battery time.

It might just be that your dealer never Fully charged the battery from the get go.:dontknow: