As Tuttle said, if he's a radio personality, chances are high that he has an employment contract. The contract will likely have "for cause" and "not for cause" termination language.
Lack of notice, being fired on the phone, does not play well with juries, and probably doesn't comply with the contract.
If there's one rule in firing people (and I have had to fire my share in the past, too), it's "do it in person, and make them feel good about themselves on the way out the door".
This was an intentional kick in the teeth. Say what you will, Axe is going to get paid.