Not able to file GSTR 10

i have cancelled my GST, was not aware of GSTR10 and itz been a year, now when i try to file gstr10, it gives error stating GSTR1 for Jan2020 is not filed. i remeber filing nil return, but it shows submitted and GST3B for that period is filed and not let me file gstr1 now. 

I'm stuck not able to file GSTR10 - with late fees accumulating alarmingly. 

Raised complaint with GST portal - in vain, ticket is open and no response till date

Can anyone please guide me on this. Thanks in advance