Immigration Law Questions? Ask an Immigration Lawyer.
Thank you for requesting me.
To be clear you had a change of petition and new approved H1B to begin 10/01/15.
You never went to work for Co A.
Co B filed a change of employer for you but you had no pay stubs to show you were in status working for company A on 10/01. Instead you went to work for Co B.
USCIS denied your petition or approved the petition for B without approving a new I-94?