Can a player use both a readied action and an immediate action?

Character A readies an action to counter a spell if Enemy Wizard casts a spell

Character A is then attacked by Enemy Rogue, and uses an immediate action (like Windy Escape, or in this example, Emergency Force Sphere) to avoid being hit.

Enemy Wizard was also secretly holding a readied action for if Character A was to cast a spell, as Enemy Wizard knows Character A is also a caster.

So: Character A readies an action to dispel Enemy Wizard if he casts spell > Enemy Rogue attacks Character A> Character A immediate action Emergency Force Sphere> Enemy Wizard’s readied action dispel Character A if he casts a spell goes off on Emergency Force Sphere > Character A’s readied action dispel Enemy Wizard if he casts a spellgoes off on Enemy Wizard’s dispel

DM Ruling: Character A can’t use his readied action to dispel Enemy Wizard’s dispel of Character A’s immediate action because a readied action is an immediate action, per:

Immediate Reaction: A readied action is an immediate reaction. It takes place after your enemy completes the action that triggers it. Interrupting an Enemy: If you want to use a readied action to attack before an enemy attacks, you should ready your action in response to the enemy’s movement.

Is this correct? Or what should actually happen here?