Remember how that OV 15 I ordered from ebay arrived broken? Well, they sent a replacement light but the UPS tracking said it was damaged. They sent a third using USPS and it never came. It was supposed to come weeks ago. I have tried contacting the seller for the past few weeks now and they haven't responded. Any advice on what to do?

Try contacting eBay.
Why not run the cobrahead without glass?

Try contacting eBay.
Why not run the cobrahead without glass?

it's metal halide plus it looks tacky without it.

Where is the 3rd bowl ? Can it be traced ?

There is some chance that the seller thinks you are trying to cheat free extra bowls out of him. See if you can get documents from UPS/USPS confirming the damage and where is the 3rd bowl. It would be fair that if the post companies pay for the damage, the seller gets the money they paid, check whether there is a case here