Did you sign anything that said your deposit was non-refundable? If so, it might be hard to get it back.
I might recommend if they wont give your deposit back to not cancel the order just yet. Even if you are going to go elsewhere... Here is why.
I had a $1k down on a dealer inventory order, they even let me change the color (this was back in September.) Then this group comes along and I realize I can save a ton of money ordering through Granger. So I place a 2nd order through Granger and ask for my $1k back from the local dealership. They say, no can do... you signed a non-refundable deposit, which I did.
So I say "ok", and keep both orders coming. Then as soon as the dealer inventory order hit the lot, I asked in a different way... I said, "Hey, my plans have changed and I'm not sure this truck is going to fit my needs... could you guys want to sell this truck off your lot?" They said yes, and gave me my $1k back.
Might not work for you... but with the inventory shortage, I think your dealer will have a lot more motivation to give your deposit back when he has that truck on his lot then now we he has you locked into a future contract.