I got a letter from the ISP couple of weeks ago telling me that my instructor permit was revoked - after waiting on the phone for over 30 minutes I found out that my NRA credentials had expired. Sent I SP the scan of updated credentials. Hopefully keeping my fingers crossed.
The bad part was that they letter did not state why they were revoking my instructor credentials.
The good part - the lady at ISP on the phone was very helpful.
Too bad you didn't see this thread sooner!