ok, now that I read through all of your responses. sorry, wife walked in and distracted.
you have grinding, or similar, noise, coming from compressor area, when engine runs, correct?
noise is there no matter if a/c is running or not, meaning - the outside plate is spinning or not?


this photo gives you insight on what you dealing with. you can see electrical coil that creates magnetic field, pulley with friction pads, like clutch pads, on it, and outside plate, whatever the big name is. when magnet engages, it draws outside plate inwards, towards it, and jams pulley, so that it starts rotating that plate, and the plate then engages compressor shaft. it's a simple magnetic clutch.
see the bearing in the pulley center?
if it's goinf bad, pulley will sit CROOKED on it, and will start rubbing on the outside plate.
ok, found name for it:

HUB DRIVER. so, if main bearing is bad, pulley will rub on hub driver. or magnet, or both. I have been there twice. it starts with a slight noise - wzoom, wzoom, wzoom, and, eventually, becomes a cut of saw cutting pipe type noise.

 

well, it only made the sound when the car first starts, for about 1 or 2 seconds, after that its fine... even if i shut it off and turn it back on.... so i just unplugged it for now... i noticed the other day it was really low on freon, but it was charged before that.. all that is possible, i just dont know why since i just replace this compressor this year this summer.. twice actually...this year... but im going to listen to it more now that i have it unplugged.. if it starts doing it even when its unplugged then its prob. something along the lines of what you are saying... jsut a fustrating issue..

 

I totally understand.
for the future reference, compressors are easily repaired and should be replaced as a last resort. EVEN IF THEY SEIZED.
also, whoever replaced it for you, might have simply used original clutch/pulley, and transferred it onto a new compressor, it's a very common practice. costs them less to buy a part. same goes for alternator pulleys and power steering pulleys.
at least, replace the belt.
be aware that world is full of un-scrupulous mechanics that will replace parts even if it's not necessary. but that's why you always ask them to return replaced parts to you. it's old timers rule. and that's why this is DIY forum, not I Pay Big Bucks To A Tech one.
you should have it easy on a/c use now, winter time, but you must have freon leak detected and fixed. in no time it will cost you more in recharges, if you do not do it.