Pleading the 5th is entirely supportable. Go for it.
In a criminal case pleading the 5th is saying "prove it (and you can't torture me)".
In a civil case it's basically doing a mime gun-to-the-head. "I'm not saying that I didn't. Have my lawyer negotiate the bill."
Like with Prenda, the claim is a barely-masked "you accused me of a crime, so I both get to take the 5th and deny you adverse inference". Pleading the 5th might help you in the criminal trial, but everywhere else we can say "yeah, you did it".