As far as plugs go I dont trust platinum. My buddy lost a motor because of platinum plugs. Lucky for me the heads had minor damage so I got my PI heads at a discounted price Platinum is meant for longetivity, copper is meant for performance.
Don't roll over for them! Return their shoddy product to them! If they dont' return your funds to you in a reasonable amount of time, by god, call your credit card company and charge it back! That will get their attention quickly