Most people om E bay are trying to be good  honest  businesses,however there are always a few bad apples.Usually contacting the person before leaving feedback is the best way to deal w any situation .Nobody wants bad feedback.I do everything in my power to make a customer happy.E bayers cannot control the mail,so sometimes patience is required.
If the seller is not helpful you should then file a complaint w

Pay Pal and/or E bay.Try contacting the seller First.