DELAY IN REFLECTING IN GSTR-2A (FY 2019-20) - Goods and Services Tax - GST

An assessee availed ITC in Dec 2019 to March 2020, whcih was not reflecting in GSTR-2A at the time of filing of GSTR-3B , but post filing of the same i.e in the month of May to August 2020, the same was appearing in GSTR-2A of FY 2019-20, i.e. the GSTR-1 GSTR-3B was filed late by supplier. Department disallowed the credit as per Section 16(2)(c) of the CGST Act, 2017 . I asked the department to take interest for early availment of credit, but they are of the apprehension that ITC was not eligible to be taken in FY 2019-20, hence you are required to reverse it, and you were required to taken ITC in next FY i.e. 2020-21, which now the time has lapsed. What is the recourse to it?