Gst returns

sir , i was vat tax payer, the vat provided provissional gstn  number on that number i have started my business and issued the sale invoice to registered dealer, when i went to migration the time was bared, i obtain the new Gst registraion number by providing my vat number and provissional gst number  in GST REG 1 i declair my commencment of bussines is from 1st july 2017 and comencement of liabilities also from 1st july 2017, where as the gst certificate is showing my comencement of busines is from 1 st july 2017, but i am unable to file the returns from 1 july 2017 can it posible to file the return GSTR 3B from july 2017