I would absolutely be in their showroom everyday and in their face (but in a respectful, professional way) until they make good either by providing you a properly functioning mower or giving full value that you paid towards another unit.
It might be worth it to circumvent them and calling another gravely dealer to get the name of the factory rep for your area and calling him/her and discussing your problem. However, I would make sure that you feel you've reached the end with the dealer before you do it. You may get a resolution but it will likely alienate the dealer and you will not get their cooperation willingly going forward.
Does this dealer sell any other brands that you could trade the gravely in on? If it is only Gravely they sell, then I would call the factory rep right away since it doesn't sound like you will be buying another Gravely anytime soon.
Yeah that's just it. I'm only 20 so idk if they really don't care or what. But I'm very respectful and don't wanna cause a big seen. But it needs to be resolved. And yes they also sell dixie chopper and exmarks.