Michael,
What is this guy's feedback like? Is it good?Bad?
I would tell him that you think that he has misrepresented his item and that you would either like the chip in the listing, or you would like a full return and I would also tell him that the situation has been reported to eBay(open a dispute link with eBay).
I would also tell him that you would like to work this out amicably BUT that you will not accept any alternative solution other than the ones you have suggested.
As for the bubble mailer....hmmmm...yes he is wrong but....he is probably off the hook since it was mailed between two pieces of bubble wrap.This is his scam.What did he charge for postage?Overcharge or...?
Unless he specifically stated in his ad that this was the NOT the chip you were bidding on,then he has misrepresented his product,and you can nail him with that in your complaint.Don't threaten....just make it clear that you are not happy and that you want a resolution before YOU DECIDE what feedback you will leave.
If he is an honest type(sounds like he may not be),then he will want to rectify this out of fear of a negative feedback.