Here are my thoughts....handle things yourself. Who the AF would take set of used injector they bought online from a stranger to get tested and then leave them at the shop for someone else to ship? And what shop would even consider this bullsh1t? And another thing...this whole tattle-talein' to paypal about my injectors are bad even though I didn't buy brand new ones from a reputable shop is bullsh1t too. Paypal refunding monies before products are returned is a load of crap.
Sounds to me like you need loaded in a bulls ass and schidt in the river, Kevin. Pay the man or send him some cores at a minimum. The minute you took them out of a box they became your responsibility. I've learned several things in the past 10 years. If you ship something...keep the receipt with the tracking number until the other end verifies the parts are in hand. I'm sure you will the next time, but it also seems that if you have had trouble before you would have learned. Since you didn't learn, it appears to us that you are the screwer not the screwwee.
Man up and pay the guy. You can't buy used stuff then beotch when it doesn't work like new with 5, 5000, or 500,000 miles on it. $.02