Late fee or penalty if GSTR 9 not filed - Goods and Services Tax - GST

Dear experts plz guide, for fy 2018-19: taxable supply was 90 lacs zero rated supply was 130 lacs client has not filed GSTR 9 till date. Now the case is under GST audit for 5 years (18-19,19-20,20-21,21-22,22-23).They (GST people) so far verbally told that there will be liability of late fees for not filing of GSTR9.Plz guide how to deal with. As per my understanding Late fees can be levied only when some compliance is made late.When compliance not at all made then there should not be any late fees.However general penalty u/s 125 may be imposed.Further plz guide whether SCN u/s 73 can be issued for late fee and if it yes then the time limit for issuing SCN u/s 73 has already expired. Plz guide I am bit confused.