Just realised the seller doesnt have the tickets yet, but then how can he sell them before they are even issued? Sounds well dodgy.
Have you tried posting on the ebay answer board, there are some v helpful ebayers on there.
Sorry but don't know the answer but your seller sounds most dubious to me, whats his feeback like?
You must not bid again for something you have already won, thats for sure.
pages.ebay.co.uk/community/answercenter/