Mismatch in GSTR-1 & GSTR-3B

Pravash Chandra Barick (Tax Consultancy) (14 Points)

15 July 2021  
While filing return for the month of Dec'20, turnover figure in GSTR-3B is wrongly not not shown while in GSTR-1 same is shown.

In order to rectify the mistake now, which option will be best. Please advise.