It’s usually very difficult to get parts for a compressor (although not completely impossible) usually the compressor is a not serviceable item and so your best bet would be a service/exchange compressor to replace the faulty one. You get a big discount off the new one by returning your old one.
There is a high likelihood the clutch is failing because the compressor itself is beginning to seize, very common on older cars where the system has been topped up with gas but it’s not had the appropriate amount of oil added to the system when serviced.
The down side is you’ll need the system regassing.
