Now that I'm at my home computer, it may not be "broken", but sure as shit it is the firing pin.
I'm trying to wrap my head around how it came out while all put together.
Check your boltface and see if the firing pin hole is enlarged. If it came out the front, that's bad.
Otherwise, you're looking at something else that is missing or broken, like your firing pin retaining pin.
This may or may not be a simple fix, more than likely it is not worth the shipping back to IO.
If you have the cash to buy the above mentioned FEG AMD-65 or perhaps one of the Serbian/Yugo AKM rifles
do that now. Keep the IO and fix it- come next month, it may be worth A LOT more than what you paid.