Any tips to find Ectoplasm?

I was actually able to find the Ectoplasm day one of the quest but it was too late to run to the wizard to deliver. In the morning it had disappeared from my inventory (I think that's a bug right?). I could not find it again after that. I mostly flipped between levels 55 and 65 using the elevator while occasionally going through each level when I happened upon a ladder. Was there anything else I could have done? I'm really bummed I wasted a week on the quest and want to be more prepared for the future.

TYIA!!