Copyright Law: I Posted Videos I Made Through Employer and They're Threatening Suit

I posted videos that I directed/made at work. Employer is threatening federal copyright lawsuit up to seven million dollars if I don't take them down and return all copies.
I was never instructed/warned that I couldn't have copies and I never signed anything.
I'm guessing they have a good case but I don't care. I'm 63, broke and in failing health. What can they do? What will they do if I ignore them?

Copyright Law: I Posted Videos I Made Through Employer and They're Threatening Suit