Same with the idiots on ebay, who place sales ads just before going on holiday, then disappear and aren't available to answer questions, which you need answered urgently, if you're going to buy/make an offer on whatever it is they're selling - same applies when you're a seller and have sold something in an auction to the highest bidder, then they disappear for days (or longer) before paying you!
For me, there's no excuse these days, with smart phones, not to be immediately 'on it' and contactable, when you're using Internet sites to buy and sell stuff - and if you've bought something on ebay, pay the seller *immediately*, just the same as you would in shop, and if you don't have the money right away, then don't make an offer in the first place!!
And don't get me started on the ARSEwipes who run on-line shops, selling whatever, whose website indicates that a specific item is in stock, or doesn't say one way or the other, so you presume it is, then once selected and paid for, nothing happens, sometimes for days afterwards, until you contact them, chasing shipment of your goods, only to be told that they're out of stock!!!!
If you're running a business on-line, particularly with a shop attached, then
BE PROACTIVE, focussed and efficient, and ensure that everything you're advertising for sale is marked as in stock or not - BEFORE taking folk's money!!
Marco.