invoice number and date

Dear Sir,
Good evening

We have planned to dispatch and export invoice number allotted shipper lables printed and stick on the shippers 900 (corrugated boxes). but due to some reason it was delayed 3 days and next 2 invoices prepared and dispatched on the same date. Now Can we keep same export invoice number or else skip the export invoice number. or else mentioning actual dates of invoices at the time of dispatch. Please help us to comply with GST.