Provide a demand letter to the shop.
You could buy the machines from the pawn shop so you have them. Then sue the shop for the amount of purchase. If the total cost is under $5k, it's small claims. You can only add a couple hundred in attorney fees.
The shop probably won't sell them to you knowing a lawsuit is forthcoming. In which case you just have to go through the motions (starting with a demand letter).
I'm not a lawyer, but I've had to sue to get what's owed me.