Should I stay or should I go?

During a Modern PPTQ, Andy casts Collected Company. As it resolves, he puts Murderous Redcap and Kitchen Finks onto the battlefield and says “Two to your face.” He then puts the other four cards on the bottom of his library. Nolan grabs his pen, and at that point Andy realizes his mistake. “I couldn’t have chosen the Redcap. He costs four. Judge!”

What do you do?

Judges, feel free to discuss this scenario on Judge Apps!

Answer
This is a Game Rule Violation for Andy, he resolved a spell wrong and we give him a Warning for that. Nolan gets a Warning for and a Failure to Maintain Game State as he had plenty of time to catch the mistake.

In this scenario a backup fits very well, we take the 4 cards from the bottom of Andys library, the Murderous Redcap and the Kitchen Finks and form the Set of Collected Company again for Andy to resolve the spell correctly.