The only guidance given the FAA Inspectors is:
1) Enter the correct limitations.
a) Enter “HOLDER DOES NOT MEET THE PILOT-IN-COMMAND FLIGHT EXPERIENCE REQUIREMENTS OF ICAO” if the applicant meets the requirements of § 61.159 .
b) Enter “HOLDER DOES NOT MEET THE PILOT-IN-COMMAND AERONAUTICAL EXPERIENCE REQUIREMENTS OF ICAO” if the applicant meets the total flight time requirement only by applying § 61.159(d) and does not meet the criteria of § 61.159(e) .
c) An inspector should remove the limitations listed in paragraphs K1a and b above when the applicant presents satisfactory evidence that he or she has met the pertinent regulatory requirements.
They don't really say how you present your evidence.
What do you mean by saying you've had no luck contacting the FAA? The one time I've had a certificate come back wrong, I've found the Airman Certification Branch in Oklahoma City helpful.