If you know of a replay transaction, or had one happen to you, please post the transaction number here. We are working on making a block explorer that can track transactions by address, which will make lookups easier. After the mandatory software upgrade, the Zen team should be able to go through the replayed transactions, verify what happened, and work to find the missing Zen.
If you sent Zclassic to someone, and the transaction was replayed in your Zen account, it was probably sent to the same person. Ask them to import their Zclassic keys into a Zen wallet and see if they got your Zen also. If they did, ask them to send it back. It might be the easiest way to fix the problem.