GST REGISTRATION CANCELLATION

Yes you have to unless the rejection is done

Dear Naveen
The proper officers has to issue order for cancellation within 30 days from the date of of application.

Kindly recheck your status Of registration.

Check it again and if not approved till date, then contact jurisdictional officer.

it is pending for processing and not cancelled yet 

now officer served notice to pay penalties / late fees 

1.Reply to the notice severed by the officer stating your ARN which was generated after application for cancellation.
2.Raise a query on the portal or contact your jurisdictional officer

department asked to pay penalties via GSTR_3B as they declared defaulter for non - filing of returns 

In the given case , 

there is no default as a taxpayer , 

as the taxpayer took registration in the month of Oct 2020 and also applied for cancellation in the same month but not filing returns 

now the taxpayer has to file gstr_3b with penalties (no option) and if taxpayer not filed returns still then penalties will get higher day by day 

Sorry i don't agree.
First of all Your ARN should be closed within 30 days from the date of application.
As it is not closed and still under process you should definitely raise a query.
You should clearly mentioned the situation while replying to the notice.
Rules are there to follow. If taxpayer has applied for cancellation there is no reason for making taxpayer wait and then Compal him to pay.

Please try any of the two else visit the jurisdictional.