CANCEL OF MIGRATED GSTIN

I CLOSE MY BUSINESS ON 30.6.17 BUT MY VAT NO HAS BEEN MIGRATED BY GST ITSELF .
I NOT FILLED GST MIGRATION FORM BECAUSE I HAD BEEN CLOSED BY BUSINESS.
BUT WHEN I SEE IN PORTAL AND FOUND THAT MY VAT NO IS MIGRATED.

NOW I LIKE TO CANCEL IT ,WHAT PROCEDURE I SHOULD TAKE FOR THIS .