Guild Wars 2

I opened the Black Lion Trading Gem Store only to discover 500 GEMS were missing. I had not made any purchases, redeemed any for gold or made any such transactions. But my gems are gone, correction half of my gems are gone. I had a total of 1,000 a few days ago, now I have 500 and as stated I made no purchases with my gems.
My last purchases with gems were for a Bank Tab Expansion and a mini Snow Flurry Dragon, but that was weeks ago (during Wintersday for Bank Tab and prior to or early Wintersday for Mini Snow Flurry Dragon).
I had 1,000 gems in my account on Monday, now only 500. Again I have not made any purchases or redemption of gems.
It takes a lot of time to accumulate that many gems. What a waste if someone can just walk in and steal them.
Please Help?!?!?!?!

We can’t help you; you need to contact support. http://help.guildwars2.com/anonymous_requests/new

Rose is right, we can only tell you what might have happened.

1) You made a deliberate purchase but have forgotten about it. This has happened before to other people and is more likely to happen if you make an impulse buy. I haven’t been in-game for a bit so don’t know what currently costs 500 gems, but backpiece/gliders seem to be around this price.

2) You made an accidental purchase. This can happen too. Cat sitting on your mouse, perhaps a drunken purchase. It might be worth checking your in-game mail and gem-store history to see if you have anything to pick up from the gem-store.

3) You miscalculated the total number of gems you had. Mistakes happen! This has happened before, too.

Very unlikely:
3) Somebody hacked your account simply to send themselves a 500 gem item and nothing more. I seriously doubt this happened. But it wouldn’t hurt to change your password anyway, just in case.

4)There was a bug in the gem-store and you lost 500 gems. This probably didn’t happen either- because the gem-store is partly dealing with real-life currency, I would assume it has to be very secure and bug-free.

I don’t mean to sound patronising or condescending, but most of the time instances like this are down to user error rather than somebody else. That doesn’t lessen the shock of feeling like you’ve lost a bunch of gold/money, though. Just feel safe in that if something has seriously happened, you’ll probably be reimbursed, but expect that it was probably a simple mistake on your behalf.

It’s what makes us human after all!

Regardless of what happened, start by following the link Rose provided: Customer Service is always the best place to get help for account issues.

And I’m afraid Crimson Clouds is also correct: it’s more common than any of us would predict how often someone claims to have lost gems (or gold) and it turns out to be a misunderstanding of some sort. In the rare cases something else happened, Support remains the best resource to resolve it.