Complaint filed with FTC.gov:
https://complaints.donotcall.gov/complaint/complaintcheck.aspx?panel=2
"You may also file a complaint if you received a call that used a recorded message instead of a live person (whether or not your number was on the Registry)."

The CLEC that operates that prefix (itltd.net, 206-666-4991) is International Telcom Ltd (formerly Telcom Design), publishes no contact info other than their WHOIS info, and states they have trademarks for robocalling systems, Kallback, Callback, and Faxaway.  Also uses 206-203-2524 for illegal robocalls.