Question: I don’t know which Moen cartridge I need to replace in shower. I have removed old cartridge in pieces and replaced with the wrong one, I guess because it is leaking worse now. I also could not get clip back in.

Answer: 
Call Moen customer service. I've dealt with them before and they're good. They'll probably ask for pix while you're on the phone. They should be able to supply you with the correct cartridge.
If you couldn't get the clip back in, then you either installed it wrong or it's the wrong cartridge. Moen doesn't change their cartridge design as often as other manufacturers and most have that clip that ensures the cartridge is in all the way and lined up right. Take the pieces to a plumbing supply store if you can't get the cartridge you bought to work.