I guess you payed via credit card outside of paypal? If you payed outside of paypal, or with it, you will have no problem disputing the charges and getting your money back.
I would simply email the guy (he's probably reading them), and just simply state if you hear nothing from him say by...this friday the 17th by 5pm, or something like that.....you are going to notify your credit card of a fraudulent charge.... which it is, if you never received the product. Either he'll contact you and resolve it, or worse case scenario you'll get your money back. Simple as that.