Hey there, a friend of mine just linked me this topic. I do a ton of buying and selling, so I don't remember the transaction specifically. However, the only mw long espada I remember buying was for 355k, so it was probably yours.
If I'd heard about this earlier, I'd refund you your item (as I've done with other people who accidentally listed their items for no heirlooms/bugged amounts of gold, etc.), but this was almost two weeks ago, and I traded it to one of my friends, and he traded it to someone else, so I really have no clue where it is now. It sounds like someone with access to your account sold your mw long espada for roughly the same amount as the axe cost, then bought the axe.
In regards to admin action on this, I asked if any of the devs on IRC would be willing to backtrack this, but they take a very hands-off approach to the market, so don't hold your breath.