Character Bricked and Cannot Continue

Hi,

I just killed the boss in act 3 (cruel difficulty) that drops the large soul core. Before going to use the core I went to go to the Temple of Chaos and when there I attempted to put the soul core in my stash...
Unfortunately the weird bug occured where when you have stash open and press triangle to store an item the soul core was instead dropped on the floor but disappeared so I couldn't pick it back up.
Issue is I can't progress without it, I recleared the boss in hopes it dropped again but it didn't.

Can the item be restored to my inventory please?