Exported goods destroyed before EGM filed

JANAK TANNA (STUDENT) (90 Points)

14 September 2018  
We cleared goods today 14/09/18 from factory for export. The shipping bill was filed on " export with payment of IGST".
But the truck met with an accident between the factory premises and Indian port and the entire goods got destroyed.
Now obviously EGM will not be able to be filed as export has not happened.
Now what is the remedy of this situation in GST?
Whether we should show this invoice in GSTR3B & GSTR1 of September,2018?
Is it ok if we drop this invoice in GSTR3B & GSTR1?