Simply state:

I am sorry you're having a bad day but that doesn't give you the right to abuse me because of it. When you feel that you can discuss the matter in a more civilized manner, please call back! ... Goodbye!

Don't forget to say goodbye ... It ends the call properly and protects you legally.

Contrary to popular belief - even if the boss says to suck it up - we do NOT have to accept abusive, bullying behavior on the job!

If that's what's expected (and money be damned!), I would seriously reconsider working there because if that's what the boss expects of their employees, then they are also exhibiting toxic, bullying behavior!

Just my two cents, and for what it's worth ...

Sincerely,
Pfrog!