Old ferrule stuck

Hello
Two problems..
In attempting to replace a faucet angle-compressor the old ferrule on the 1/2 copper pipe is stuck . How can I remove the ferrule in this situation?

I attempted to use the new compressor and old ferrule & nut, the new compressor when tightened to the old nut has play and the entire unit can spin on the pipe which allows for super water spray..
What could I not be doing correctly..

(In order to have water service again I re-installed the old compressor to the stuck ferrule & old nut , there was no movement. it works fine. ??

you need this

https://terrylove.com/forums/showthread.php?t=10524

Thank you for the prompt reply.. Have a good evening.

ferrule

You probably have one of the old coarse thread nuts which will not work with the new valve, although I have know some people who got them together using a couple of big wrenches and a lot of force.