It's not Olights fault your light is green (not entirely anyway.) CREE makes the LED's not Olight, but it is up to Olight what LED's goes into their lights.
I'm finding that most of my lights with the XML (cool white versions) are all somewhat green...some worse than others. It seems to be hit or miss. I own the following with the XML LED in em:
Olight M21X - mildly green, and doesn't bother me much.
Zebralight SC600 - one of the worst GREEN tinted lights I've seen...great light but aweful tint. Got unlucky here.
Zebralight H600 - mostly white, and very nice.
EagleTac M3C4 - mostly white, and very nice.
Quark 123x2 Turbo X - greenish tint, somewhat annoying.
Quark X NEUTRAL AA2 Pro - very very very very very very very nice neutral tint.
Quark X NEUTRAL AA2 Tactical - very very very very very very very nice neutral tint.
I will seek to purchase NEUTRAL tinted lights when possible. I have grown tired of the tint lottery that goes on with lights no matter who the manufacturer is. The source of the problem is with the manufacturer of the LED ---> CREE. Some of their LED's come out close to perfect, and the rest are less than perfect all the way down to awful. Unfortunately it is luck of the draw that determines what you get. Flashlight manufacturers could be more picky about the tint of the LED's that goes into their lights, but this would probably limit the number of lights they'd sell. Zebralight has been known to be picky about (some) of their lights, and I have seen this slow their sales down. It is currently happening with all of their neutral tint lights. They stated that they are waiting on the tint they "like" before making anymore neutral tint lights.
Maybe you can send the light back. Can't hurt to ask the dealer you bought it from.