I've had some shockers and eBay by far has the worst customers I've ever dealt with in 10 years in business (website and physical store). You just need to accept that you will get rude people now and again. I post a lot of items without tracking and explain they don't have tracking which no one ever reads and argues afterwards when there is a problem. As some others as mentioned, I have to offer the cheapest postage method to be competitve or else I would get no sales. When something goes missing, I ask a number of questions (confirm address etc) but then will mostly always just send another one out and accept the loss. Afterwards I get a lot of negative feedback even after I have lost money by needing to send another, but most of time if I put in a feedback removal request and explain the situation to the seller they will accept .