27 August 2018
Login you GSTN, Go to Srvices, Go to refunds, go to application of Refund and go to Export of services with payment of tax and file the applicatiion in which month you paid IGST.
28 August 2018
There is no need to apply any refund application for exports of goods with IGST payment. For these cases, Shipping Bill is deemed to be the refund application. Just take care while filing GSTR-1 and GSTR-3B.