REFUND

I AM A SERVICE PROVIDER AND I HAVE UPGRATED FROM SERVICE TAX TO GST BY FILING TRANS-1 FOR AVAILING BALANCE OF ITC IN SERVICE TAX.
NOW MY BUSINESS IS NOT RUNNING WELL AND OUTPUT TAX IS ALMOST NOMINAL , BUT I HAVE UNUSED ITC IN MY CREDIT LEDGER IS AROUND 3 LAKH. CAN I TAKE REFUND OF SUCH UNUSED ITC????? WHAT IS THE PROCESS FOR CLAIMING REFUND OF SUCH ITC.????