I have a Moen, single handle faucet in my tub that began leaking. I went in to try to remove the cartridge, but it’s been in there for potentially 25 years and didn’t feel like leaving. After working for a while the inner assembly of the cartridge pulled out, leaving the outer casing still stuck inside the pipe. I’m not liking the idea of having to replace the whole pipe unit, but I’m running out of ideas. Can you help? Thank you.