Air conditioning problem

I have a strange problem in my air conditioning which was something never heard of to a lot of mechanics. I hope you can guide me over it.
Well last week I was traveling with my car in a three hours trip journey; after two hours the AC suddenly stopped cooling as I was slowing down in a a checkpoint. The fans were running blowing hot air whenever I press "auto" button on my AC. The car has a digital dual zone AC.
I did continue my journey until I arrived to my destination, and while I was parking I heard some slight noise similar to a bearing defect. Anyhow I did park and while on idle I decided to run my AC and press on the acceleration pedal to see how the engine will sound. Once I did that I heard a rattling noise. I took a look to the serpentine belt under the hood and it was fine. I turned off my AC and tried the acceleration pedal again, the sound was normal. I traveled without AC for extra three hours and went to a mechanic for fast checkup. The mechanic have done the followings:
- Checked the refrigerant charge and it was okay
- Checked the voltage going to the AC Clutch socket and it was okay.

Then after close look, he found the clutch dropped from the compressor and the lock bolt was lost. He told me that was strange and I will need a new AC compressor since the clutch won't be available for sale alone.

Anyway, he ordered a used AC compressor for me and installed it, but unfortunately the clutch did not engage at all once the AC is on. He installed another clutch after testing it first with a twelve volt connection and it did engage, but he did not turn the pulley as I can remember. I have seen it engage myself.

Well after installing that compressor and charging the refrigerant, the AC compressor did not turn on as pressure did not increase and vents was still blowing hot air. The mechanic checked the clutch engagement sound, but he thought that the clutch coil is not good enough to generate the electromagnetic field to attract the clutch well. Anyway, he did not really checked whether the engagement is turning the compressor or not. I will have to check for a third compressor for that issue but I might have some doubts that it is not the clutch and maybe the compressor is locked up.

When the mechanic inspected my failed AC clutch, the clutch teeth was damaged so can I say this was the rattling noise I have heard? And this is because the AC compressor had locked up. What do I need to check before installing a new AC compressor? This is my thoughts and not the mechanic as I think something is locking up the compressors, but in this case I have to say why I have not heard other rattling noises when I installed the last AC compressor.

Your guidance is highly appreciated.
Regards,
Khaled