Power of attorney

DEAR SIR , I HAVE A COMPANY POWER OF ATTORNEY , POA GIVEN TO ME FROM STFC COMPANY FOR LEGAL CASE SUIT FILE AND APPEAR. BUT BEFOR ME COMPANY EMPLOYEE HAS BEEN LEFT SERVICE FROM COMPANY . I HAVE SUBSTITTUE POA IN LEGAL CASES IN THE COURT COMPANY CASES EG.--EVIDENCE 138 NI, EXECUITION . COURT IS NOT SUBSTITUTE ANY MATTER .AND TO BE REJECTED MY COMPANY CASES . SO PLZ GIVE ME LEGAL RUILING AND ADVICE ME FOR SUBSTITUTE COURT