At this point, slowly acclimate it to the sun, keep it warm and don't over water it. I have kept my citrus in an unheated garage for minimum 2 months without any sunlight, but not quite completely dark like the box. You may get lucky and the tree recovers. If anything, you learn something new by this. Now the dilemma is do you notify the company who sent it that the tree finally arrived? Everything shipped now has an electronic trail when delivered.

Thanks, Denise! They were VERY accommodating sending the new trees, so I will let them know. I hope it does recover .. it's stuff hanging on to some blossoms and some fruit!

Please post a picture so that we can get a better idea of with what we are dealing.

I would put it in bright, indirect light for two weeks, then in direct sun. The white mossy stuff is probably mold. See if you could wipe it off with a damp paper towel.

Vladimir -- Pix attached. Thank you for advice!

The tips of the new growth appear blackened as well ...

That tree really looks good for sitting in a box for 6 weeks. I think you have a good chance of recovery. I expected something much worse. Good luck.

Kat, the tree really does look quite good. I doubt that you will have problems with it. And don't worry about the dead tips .

It looks way better than I expected! And makes me feel better about my order arriving next week that will take 7 days to get here.

Thanks all! Final question: the whiteish stuff in the third picture is mold? Should I wipe it off or address it in any way?

I couldn't see really anything white because I couldn't blow up the picture.

I am not sure because I could not see it well but I think it is some sort of chemical that was sprayed onto the plant. Whether it is mold or chemical, you can wipe it off. If it is chemical, it may not wipe off. If it is mold, I doubt that it is harmful.