No. Do NOT chalk it up to experience.
You have the ammo in your magazine to open a can of whoopass on this guy if, indeed, he did scam you, and you paid with a USPS MO.
Scam artists are betting you will "chalk it up to experience" and leave it at that. All it does is embolden them and give them reason to try it again...often times with the same part.
Now, on the side of fairness, maybe something happened. He could be in the hospital. My suggestion is to send him another volley of emails, informing him of your intended actions with the Post Office and the possible consequences. Then give him a 'drop-dead' timeline with which to respond in before you take such actions. You might be surprised how quickly you receive you parts and/or communication.