Paladin - Claiming the light bug

Hi,

On the Claming the light lvl 12 quest, I got a bug when I used the empty shimmering vessels into one of the magisters. The item disappeared and I didn't get the filled vessel. I think I moved the character while it was channeling and then I didn't get the empty vessel back.
Is there a way to get again the empty shimmering vessel? I'd like to finish the quest in order to get the Redemption Skill

Thanks!

Is there any way to restart the quest?
How can I get that spell otherwise?

If you got an item from an NPC, you can probably request back the same item from the same NPC. One option is to abandon quest and retake it.