2004 Honda Civic groaning noise and losing cool air

Air Conditioning problem
2004 Honda Civic 4 cyl Front Wheel Drive Automatic

QUESTION:

What can cause a low groaning noise when the
a.c. is on for a few minutes and then, the air
is no longer cool - but hot. I have had the
filters changed, the a.c. fan checked, and then
coolant was put. The Honda Dealership kept it,
but not sure what it is since they didn't run it
long enough to see the problem.

Please advise.