Air Greenland has an agreement with ARC (Airlines Reporting Corporation) and U.S.Ticketing agencies can reach out to ARC’s Customer Care Center directly for any assistance regarding ticketing.
Here are the contact information for ARC-CCC:
Phone: 1-855-816-8003
Note: The agency will need to select Option #1
Email: ccchelp@arccorp.com
However, sometimes questions can be related directly to the airline: