Item disappeared
You will have to submit a support ticket for assistance. The support link is at the top of the page.
The Burninator
Before you contact support try searching for it using gw2efficiency.com. Once you’ve signed up for it you can use it to search your whole account for lost items. You can search by name or you can search by rarity. It will show whether or not you have the item and where it is if you do.
Be careful what you ask for
ANet may give it to you.
ANet may give it to you.