Well if they were for Take That in Manchester you wouldn't get in unless you could confirm who had bought the tickets: (though I didn't think even the seats had been allocated yet, just in blocks, never mind tickets being produced)
http://www.take-that.co.uk/ns/news.php
�30 is about right for Royal Mail compensation. Go back to the ebay seller. TBH though, they might not want to give you their name and address etc or them bother having to get more tickets.