I think you were fortunate to receive a neutral.  I would have left a neg!

Sometimes it takes hours to find something with the way things are set up on here with search.  And to find something wanted & probably collectible, buy it and then find out the seller doesn't have it in the first place is very disappointing.

Buyer may not be on eBay every day - and may not have known you didn't have what you advertised and just kept on expecting it to arrive.  Buyers have up to 60 days to leave feedback.

I practically have a panic-attack if I can't find something that I may have advertised for a few months.