My Salary for the month of March and April Still not paid. I moved to a new company

You are entitled to your wages, regardless of whether your prior employer has been paid by its client for the work that you did.  This is a common problem with Visa workers like you.  Your entitlement to wages is covered by the Federal Fair Labor Standards Act and, if your employment was governed by Pennsylvania law, the Pennsylvania Wage Payment and Collection Law.  You can initiate an administrative claim with either the U.S. or Pennsylvania Departments of Labor, Wage and Hour division or you can file a private lawsuit against your former employer.  In some instances, the principal owners of your employer can be personally responsible for your unpaid wages -- suing them in addition to the company usually gets you a lot of attention!   The private suit will probably get you faster results.  Both statutes require employers to pay your attorneys fees plus penalties on top of the unpaid wages.