You must be joking

能不能打電話要求不去（因為那時已經開學了）?

He needs to show up, period. A subpoenais not a joking matter. Everyone has to respect that. Unless you are so ill that you cannot physically go to the court, you need to show up. School started? You must be kidding. If he does not show up, the legal trouble will be far more than the tax issue. He could be ARRESTED on CONTEMPT of COURT WARRANT.

You are not naive, you are too naive.