You did not get a reply because we simply ignore support requests where users forget or don't save their private keys, this was the general consensus when we had the same issue a few weeks ago.
My opinion is that you should still reply to received support emails, and write him at least one simple explanation, this can even be general reply email.
Agreed. It's unlikely for all users to read everything on Bitcointalk.
What if we refund this user based on the guarantee letter and then we receive another support request from 'someone else' with the same guarantee letter while also having the private key telling us that he doesn't see his balance on Whirlwind anymore and accuses us of scamming? Do we refund that user as well?
How can there be two (or more) exact same letters of guarantee?
(Not counting that someone hacks in user computer and steals the original document).
It could have been a hack as you say, but it could also be the person with the LoG pretends to be someone else. It could also be the website itself claiming to have received the LoG by someone else already, and there's no way for the user to confirm this. Either way, it's opening up a can of worms.
As an extreme solution to prove how important this money is to me right now I can fully DOX.. What more do you need @whirlwind.money
There's no need to DOX yourself, and it doesn't help your case either.
I've just sent the private key to support email.
That was dumb. In Bitcoin, ownership is proven by signing a message, not by sharing a private key. Now you're no longer the only owner of that address.