Retain a good lawyer. At the very least, it's cheap insurance; that lawyer should be able to advise you as to what the pawn shop may or may not try to do in an effort to get you to give up those pins. In fact, try to get a lawyer soon enough that they can be present alongside the sheriff when you attempt to get the machines released so that you can show you mean business. And be prepared to ask, right there, that the sheriff file charges of them trafficking in stolen goods, and show you're absolutely prepared to file a civil suit right alongside the criminal charges.

Basically, show it's going to be cheaper in time (and possibly money) to just give the machines back to you.

The way I look at it is, if I had to go back after having my authorized representative stone walled, taking time out of work to do so, I'm going in to make sure I'm either leaving with my 10-30k of property, or his ass in a tight sling, with that second visit.

Indications are the police already know the games are there. Destroying them now would open him up to more charges, and less ability to plea bargain against the thief.

That's why I recommended the lawyer. And having filing criminal charges as one of the options. He had stolen property; getting paid for should not have been on the table, and he should have been arrested right there for demanding it.