merchant export

Danish (Accounts Executive) (73 Points)

27 May 2018  
we had supplied goods to merchant exporter for third party export @ 0.1 % igst but merchant exporter failed to export the goods within 90 days hence making him failed to avail the above 0.1 % exemption.
so being a supplier what action needs to be taken from my side do i have to revise the invoice with 18 % gst or issue debit note against the same.