I agree it was a bit of an extreme decision, i personally myself would have gone through and seen which accounts had multiple characters from the old server and linked their IPs so that they the players who did do it would have had their item content removed instead of the whole server.
At the end of the day whats done is done, i'm not sure if i can restore the items but without the old file i cannot do much sorry.
On the bright side the EXP and Drop event is on so you can go hunt for items back quickly?