GST Credit

You should have received the goods to claim credit

you will take credit in the month of march.18

IN THE MONTH OF APRIL 

Fot  ITC  not only you have to received the goods correct with   GSTN no invoice  , but  also supplier  must pay  GST  collected  form you to the GOVT and he must file retrun .Otherwise  you will  get  provisional  credit  only for goods received in the month of april .