Your seller is still on eBay and you bought the item within the last month, so you should still be able to use eBay's money back guarantee if it hasn't arrived. You must open a case within 30 days of the latest estimated delivery date.
Saying that eBay "didn't want to know" tells us nothing. To advise you correctly we need to know exactly what procedure you followed with eBay, and why they were unable to help.
If you haven't already opened a case, you can do so now. I you opened a case, but lost it because the seller provided tracking proof of delivery, I'm afraid you have a problem. Theft of parcels from the doorstep is becoming common, and the seller isn't responsible for what happens after items are delivered. If it was delivered to the wrong address you may be able to appeal.
This is the best advice I can offer with so little information.