Hi, you poor thing. Last thing you need is a lecture, I'm sure you feel bad enough as it is. Definitely speak to ebay in person, contrary to some people's opinion of them they will be sympathetic, and be upfront about the whole situation, you don't know until you ask for help what they will do. Yes, I am speaking from personal experience. Also, make sure you follow up on feedback left for you, at least you can counter the comments already left by that one buyer (which only counts as 1 neg on your total score) and def communicate with the other buyers. An explanation with the promise of a full refund will almost certainly satisfy most,  As far as your financial situation is concerned, tricky, make sure you contact paypal as well by phone, communication is important as it puts more of a personal spin on things and most people will try and help out someone if asked. Good luck and I hope it resolves without too much more distress. xx