Due to many of technical reason you have to face rejection of IGST refund i.e. due to change of bankers details, due to shipping bills validation errorr or much more.
Step : if all the Shipping bills validated successfully with "SB000" although generated scroll rejected by PFMS , in that case you have to ask PFMS about the technical issue arises. write to helpdesk-pfms @ gov.in, they will inform you details about rejected.
1. if bankers details not matched than please submit AD code letter, Cancel cheque and covering letters, with the help of your CHA to the PFMS desk at related port.
2. Reach concern ports local IGST help desk with the help of your CHA with the details of rejected shipping bills . Request them to generate temporary scroll against rejected scroll.
After submission of above letters they will help you to re generate temporary scroll to get IGST refund.