Sellers on eBay do not like when bidders bid and dont Pay, not only do you have to Beg for your Fees Back, you dont get a sale that you were promised.
I will not disagree with he Psak if the bid was not already made, however if the Bid WAS already made there could be an issue of Stealing and Genevas Daas as well since the seller thinks he will have a sale and you dont pay.
eBay charges Fees as well, most of those fees are refundable if the buyer backs off, but it takes a few weeks to get them back, but some fees might be lost and you cost the seller money depending how he listed it.