We are a sign contractor (subcontractor to a national sign company who contracted with the client. We took too long to get set up with LevelSet and missed our prelim notice window (job started on 2/15). Our invoice is now past due and our customer is not returning calls. We made contact with the client directly and their legal dept is "looking into" direct payment to us. I would like to apply pressure but not sure what the best way to do it.