U2713HM, Ebay purchased, Dead Pixel, need original order details?

I purchased a Dell U2713HM through Ebay in December last year. The monitor now has a tiny black line in the middle which appears to look like dead pixels. I looked up on the dell product support to check the Warranty on the monitor which ends on the 3/12/15. The monitor was originally purchased from Dell on the 3/12/12 and I purchased it on the 8/12/12. Just 5 days after the original purchase. I contacted the seller through eBay, which is a business that sells a number of dell products and other such PC items but they never got back to me so I rang the Dell support line. In the phonecall I was told to give the Service Tag for the item, which I did. I was then asked to give my name and details which I did too. I explained my situation and was told that the monitor would need to be replaced but to continue I needed to give the name and address that was on the original order from Dell. Without it I wasn't allowed to continue and was told to contact back once I had gathered the information. I have since tried to contact the seller through eBay but again there's been no message back from them so I'm stuck with a monitor that has a few dead pixels in the middle of the screen with no way to get it looked at or replaced. How can I go about getting anything else done? The monitor still has a Warranty that lasts for just over two years, but why do I need the original details to "match it up with what's on the system?". Just annoyed I spent so much money on a monitor and now I'm stuck with a defect when the monitor is still under warranty.