I want them investigated.
Buyers don't have the right to "demand investigations" of sellers. The way to get eBay involved would have been to use their money back guaranee, which you unfortunately left it too late to use. eBay will have no interest now.
Don't expect buying on eBay to be like the shops. You were even warned in the user agreement that eBay does not generally make checks on sellers or guarantee that items for sale here will be truthfully described, safe or even legal. Would you have trusted a shop or online seller who stated this?
eBay does provide its own money back guarantee for most items sold here. But if you didn't open a case within the 30 days time limit of the estimated delivery date I'm afraid that will be the end of it as far as eBay is concerned.
I fear you are almost certainly now also the time limit to get help from your payment provider, e.g. credit or debit card. Their time limits are usually about 90 days.