I am working for GC for California Public works and one of sub didn't get paid due to several reasons (we have hard evidence that this sub didn't perform such work so we didn't pay them). Now I received Notice of Nonpayment from this sub. I researched a bit but in order to file mechanic lien or bond claim, sub must have submitted 20 days preliminary notice. This sub didn't submit prelim notice so I assume that sub doesn't have right to file a claim on this project. right? As a GC, what kind of action should we take after receiving this notice? Should we do something?