GSTR-3A notice received via mail

If an Assessee got an notice under GSTR3A via mail for non filling of GSTR 3B for the Month Oct 2018 Nov 2018 Dec 2018 upto date but he had already RC cancellation applied on 30th Sep 2018 (GST no cancellation order 16.01.2019 via email) pls suggest me what he has to do