How to contact somebody sending a complaint.

Hey all

We're an ISP and Spamcop Complaints get into our Tracker System, generating 
an Auto-Reply to the sender with an Incident ID.

This caused Spamcop to drop all Emails from our Tracker System, as most 
customer apparently do not want to get any reply (not even results) about 
the complaints they sent.


Now we got a bit a strange complaint where I would need to contact the 
person sending that complaint.
The Email is Munged and except of the receiving server I can't find any 
information to identify the address involved.

Is there a way to contact the person submitting the complaint?

Is the [email protected] valid even if answered from a different email 
address or is just everything dropped once an ISP is set to 'drop'?

Regards
-Benoit Panizzon-