Typically, you have to claim your redemption within 30 days of receiving, however that timeframe will vary based on the redemption.
Any troubleshooting for redemption fulfillment must be completed within 6 months of it's original fulfillment date, any further troubleshooting past that point will not be able to be processed.
Any redemption issues older than 6 months will not be able to reissued or refunded.