Link Intime — Non receipt of Redemption amount of Bond

Redemption amount of my L&T Infra Finance Co. ltd. under ISIN INE691IO7232 matured on 21/03/2021 and a DD was sent to my registered address but due to COVID situation the DD could not be encashed within its validity. Since then I am following up for the credit of the amount to my account but it's not happening. The mail's are only promptly acknowledged and most of the time I only get the msg "Unable to open the attachment". The various Ref Nos. for investigating are 423057/426258/426819/427735/430111/435354/436279/449129/449589&450117