Mostly use the Vehicle assistance section for questions, this is just a kind of hello area!
It's not happened to me, well not yet!
But - if it's £150 to fit a used compressor, then there's nowt else other than a re-gas to get it running again, on any car, making the assumption it worked before of course.
So do you have any options for a second opinion? With more AC experience? Of course right now the car won't go far without that auxiliary belt.
If it didn't then who knows, if it's a 3.3 it could have leaks on the pipes to the back, or the rear coil is duff (guess how I know this....) or on either version all sorts of other stuff.
If you put your car details in the section on your profile it helps nail down what we're talking about!