Some insight Judy...the email you received could very well be legit, ebay just doesn't want people using the contact member option to lead to sales outside ebay. In a way it's for our safety, but it's also because there are no fees in it for them. From our experience, although we are not 100% sure, we've concluded that the email you received from ebay is another cut and paste one from them, worded cleverly so as not to fully acccuse the sender and to kinda scare you into keeping your transactions on ebay. Personally my hunch is that ebay has an automated system of some sort that scans emails for key words, links etc. and when it gets a hit it fires off that email to the recipient. I understand what they are doing, but at the same time I think it is possible that legitimate customers can be collateral damage in this system as well. And while I appreciate any help I can get from ebay in terms of safety, personally I'll look out for my business myself first and foremost.
You handled it right by not using the links and asking to return the item numbers, to just to air on the side of caution. But this person, particularly since they have an active ebay account, could very well be a legit customer and their questions are worth answering.
As for the emails from the manufactuers with items to sell. That's just spam from China pretty much.