What are the consequences of not filing any particular return

If the registered taxable person fails to furnish the return in FORM GSTR-3 or GSTR-4 or GSTR-5 or GSTR-6 or GSTR-7 or Final return in FORM GSTR-10, the department will issue a notice in FORM GSTR-3A asking the registered taxable person to furnish the particular return within 15 days.

(ICAI FAQ PUBLICATIONS 06-09-2017 RETURNS: FAQ NO. 53)