I was searching for a USB keyboard.
If you just entered USB keyboard into the search field and searched, then most likely you would have been steered into the Keyboard category and depending on your default sort order and shipping location you would likely have seen something like 60,000 results of listings that contained both of those keywords somewhere in the title or item-specifics -- which is decidedly not the same thing as searching for keyboards with a specific type of USB connectivity. The results of such a search may have included full-size and miniature wired USB, USB 2.0 and USB 3.0 keyboards, but also USB-C keyboards and wireless keyboards with USB dongles and non-USB Bluetooth wireless keyboards that had USB charging ports, wireless keyboards without dongles and dongles without keyboards, among other things.
If the listing you purchased from actually claimed that the keyboard had USB connectivity and the actual keyboard you received did not, then you should have been able to return that keyboard as "not as described" within thirty days of receiving it at the seller's expense for a refund.
But if you had assumed that the keyboard specifically operated over a USB connection just because the keyword USB appeared somewhere in the item-specifics without actually reading and verifying that, then the mistake was yours and not the seller's or eBay's.
A better search for a wired USB keyboard (but not necessarily USB 2.0 or a USB 3.0 or a USB-C keyboard):
https://www.ebay.com/sch/i.html?_nkw=%22usb+keyboard%22+-usb-c&_sacat=33963&Connectivity=USB
Or a wireless USB keyboard:
https://www.ebay.com/sch/i.html?_nkw=%22wireless+keyboard%22+usb+-usb-c&_sacat=33963&rt=nc&Connectiv...
But even with those searches, as a buyer you should still read a listing closely to make sure that the item that is advertised is what you are actually looking for before committing to a purchase.
On eBay, sellers can be held responsible for not providing accurate descriptions of the items they sell, and buyers can be held responsible for not reading the descriptions of the items they buy.
