Credit for TDS has been claimed but the corresponding receipts/income has been omitted to be offered

A taxpayer has received a notice regarding claimed TDS credit where the corresponding income was omitted from their tax return for assessment year 2018-19. Despite submitting Form 67 and Schedule FSI for foreign income, they are unsure how to proceed as the deadline for filing a revised return has passed. The advice suggests revising the ITR with correct figures, but acknowledges the challenge posed by the expired revision window.