Your eBay advert isn’t that great.
Put the full bike name in the title (and capitalise it properly too).
List the spec, and the condition of all the bits, close up pics of drive train etc etc
If you’re willing to post it, do it properly and put a price in the listing. People will just skip over the ad if it says “collection only” even if you say you’ll box it up in the listing.
At the moment with a title of “trek fuel” and a description that basically wants you to pay cash and says “used once, genuine bike”, lots of people will probably think its stolen due to lack of knowledge on the part of you, the seller.