Can we make up the certificate of origin half a month later

Please ask: for the goods exported to Bangladesh, the customer did not tell us to provide the certificate of origin before delivery. Now after the goods are delivered, we send the customs clearance documents to the guests(bill of lading, packing list and invoice). The goods have arrived at the port of destination on June 6. Yesterday, the customer told me that the customs required the form B certificate of origin, and the freight forwarding company told me that due to the long time of shipment, the form B certificate of origin can no longer be processed.(PS: shipment of May 20th). Excuse me, do we have any other way to handle this certificate of origin?