Some altezza light makers just plain suck. sounds like you got one of those makers. chase the seller for a replacement, whether you got them from a store, or eBay...

they have tail light smoke paint on eBay, about $10.00 a can. you can also use a transparent red paint, made for models...it's pretty hard to get a clean finish with that paint, though...i've done that to my tail lights, it's good, but not great.

good luck.