While I understand your frustration, keep in mind that most people selling on eBay are not full time sellers and this is not their "line of work". If you bought something from them they have a responsibility to send it to you in a timely manner but to assume they can always jump through the proverbial hoops is somewhat unrealistic.

In the Internet age everyone is quick to complain or leave negative feedback and, in my opinion, it is far too easy to do so. My thought is that I go back in time 20 years and think, if this issue is worth writing a letter or making a phone call to someone's manager or seeing a manager in person then it is suitable to leave negative feedback. If it was not worth that effort on my part, then it is not worth leaving negative feedback. I should hope, as a business owner, that people would extend that same courtesy to me. None of us can be "Captain Fantastic" 100% of the time.

Wouldn't it be awesome if audience members could leave negative feedback every time we rushed a fill, counted off a song 3bpm too fast, forgot and left a stick bag at home...