If you've paid IGST and customs duty on a product imported into India, you may be able to claim the IGST as Input Tax Credit (ITC). To do this, ensure your GSTIN was provided during import. If it wasn't, you might need to contact the customs authorities to update your details and then claim the credit via your GST portal's 2A/2B.
17 January 2022
If the goods have been imported for business purposes, you can get the credit of IGST paid at the customs. Ask your clearing agent or the postman. But I think you have not mentioned your GSTIN when importing goods; hence, the IGST credit is not available now.