brand new fixie, different sized dropouts - send back?
If the issue was just the 1mm difference in the dropout, I would personally just file it out and note it in the Ebay feedback.  

With this one bent, contact the seller and see if there is a replacement/return option.  Failing that you could try to get a shop to bend it back and bill the seller.  If the seller gives you a lot of grief then take it up with Ebay right away.  Whatever you do, be sure to reflect it in your ebay feedback.

If using a nutted axle, it shouldn't be a safety issue but may take more effort to get the wheel on/off.