Go visit him and his shop and work it out in person. If your stuff is still sitting untouched, it's totally reasonable for you to demand it back. Settle up on any parts he purchased for you that wasn't covered through initial payment*. He's the one making it harder than it ever needed to be.
Hopefully you have receipts/proof-of-purchase for the games or something in writing about him doing the repair work for you. It'll be hard to get them back if he wants to be obstinate about it and you can't easily prove that they're yours.
*also don't pay up front. Half up front to order parts is reasonable, but people aren't motivated to finish the job when they've already been paid in full.
