@ Vijaya Kumar
If you get a parrot and teach him a line it will speak that same line after it mugs that up. Contacting Customer support in such matters is really not worth in such cases, because they are always ready with their canned responses.
It has happened many times before that feedbacks have not been removed because of some server errors or some other technical glitch.
Do you have account manager in eBay, if yes then contact her/him with all the details. they might help you out.
If not send a mail to incs webhelp with all the mails you have regarding this matter. They will help you out.
meanwhile you at least appeal for the second negative feedback in community court.
But why dont you talk with buyer and if he is ready to change his feedback, send him feedback revision request... That will immediately solve the problem.
Designer Wear at Dirt Price!
Linus Studios.