I received my delayed baggage from FRA today (flight was last Sunday).
I received 4 or 5 emails saying that my baggage was found and is on the way to ZRH but it never arrived. Sent an email last Wednesday to the ZRH lost bag adress and asked about it.
Yesterday the baggage made it on a LH flight to ZRH and was delivered today, don't know if the email was of any help or if I was just lucky.