Delete your character that has the duration item, and then open a ticket to restore the character. After you talk to the GM he should have restored the character. I recommend doing this with a low level alt or something, sometimes they can't restore it. When u log back onto it, it will still say that it has duration but it will never drop. I did this with the human orphan on children’s day, I didn't even mean to come across this it just happened to me :P I hope this works on other items
Sorry if this has been posted before all i could find was a way to do it for items that are not BoP