What would you have done?

[Tru_in_Blu]

PU signals the DDB, then calls "illegal, no pitch."

I don't think a delivery can be both "illegal" and a "no pitch". So maybe that's where the first hint is. I think a quick pitch should be ruled illegal, and if the batter decides to swing anyway, that makes it legal.

But if there's a "no pitch" call, I think everything should be re-set to how it was prior to that no pitch ever happening.

Since the BU made both calls, he confused everybody possibly including himself.

I'd say "do over".