Contact Form 7

I have a query form with a “Know exactly what you want?” check box. Everything under that is hidden until you click it. There are several Radio boxes as part of the hidden part. The problem is if you don’t select the “Know exactly what you want?” check box we don’t want any of the radio boxes to be selected or even in the email but Contact Form 7 insist there is a default selected Radio or it won’t send. How do I get round it?