A little FYI,

Today's vehicles have condensers the are impossible to clean out or repair, therefore they must be replaced if contaminated.

When a compressor goes south and distributes garbage throughout the system a bunch of parts MUST be replaced AND lines purged. This can get very expensive and involve a lot of labor. Hence the high cost to correct. If any shortcuts are taken, that allows crap to circulate throughout the system again and the cycle repeats.

In the process of attempting to save a customer $$$, they really are not doing the customer a favor by skipping what must be done to bring the system back to good operation.
As you can see there are all sorts of possibilities and it can be difficult to understand what is going on. And yet,,,,,,,,,when someone does the complete job and does it right we complain about the high cost most likely because we don't know what happens when we skip "must do" steps.
I suspect that may be what is happening with this vehicle