It look like regulation may have contributed if not forced the shut down.
Those holding ZXG tokens can claim them as ETH.
This appears to be a case of exiting rules & regulations being applied to the crypto industry.
Something akin to applying the rules for horses & wagons to motor vehicles.
Does anyone remember needing a "Flag man" to walk in front of your car, to warn pedestrians?
Time will tell
https://www.ccn.com/south-koreas-zeniex-exchange-to-shut-down-after-less-than-6-months/