Unable to remove Healing Collar

Healing collar was placed on 12/2024 post-op x-rays notes healing collar flush with platform and equal space around the sacrew within the fixture ready to place transfer coping and abutment/crown. At this point can't remove healing collar, try to reverse torque up to 50ncm and stopped with no movement of the healing collar. I believe the healing collar was placed by hand and then torque to 15ncm. 

Any suggestions how to remove the healing collar at this point? 

Thank you!

AK Aronoff