Well, the notice given could be a problem.
In your case I agree that notice was correctly given, as you informed your supervisor.
But if notice wasn't given then the employer could argue his case, regardless of the law. For example, you cannot ring your boss from the airport and demand your holidays, starting right now,.. even if you have holidays due.
Likewise, (not in your case), you cannot ring your employer from the courthouse, saying you're on jury duty.
Your supervisor should have told your main boss,.. if he didn't then your boss needs a more capable supervisor. If it's a small company then the boss may not have anticipated this, and so it's a lesson learned.