I filled out the refund form, and they offered ~$900. That seems low.
They say that no downgrade compensation is due because a portion of the ticket has been refunded. Twisted logic.

There must be a way to parse the fare components to see what is due. (?)
I flew:
1. SEA-DXB-JNB-WDH
2. WDH-JNB: downgraded to Economy
3. I did not fly JNB-DXB-SEA

#3 was 2 days after the floods. The JNB-DXB flight was canceled. The inbound had been canceled, too, so no way to get out.
Emirates suggested looking for other flights, and we'd get a refund for that. (ha! - different story)

I flew out on United that same night.