Hello Tax Payer,
It seems that you had a registration under GST but you couldn't file a GST return since you didn't start your business and now the registration number has been cancelled.
As per Section 29(2) of CGST Act, 2017, the proper officer can cancel the registration of a person from such date, where any registered person, other than a composition taxpayer, has not furnished returns for a continuous period of six months.
Now, if your GST Registration has been Suo-Motto cancelled by GST Officer, then you have the option to file GST Revocation request within 30 days from the date of cancellation order.
Any liabilities prior to the date of suo moto cancellation will have to be paid by the taxpayer, irrespective of the fact that when determination of liabilities are done.
You can submit returns of the earlier period (i.e. for the period before date of cancellation mentioned in the cancellation order), after suo moto cancellation of registration. However, you will not be allowed to file return or upload invoices for the period after date of cancellation mentioned in the cancellation order.
Also, it may be noted that Section 45 of the CGST Act requires every registered person whose registration has been cancelled, to file a final return in FORM GSTR-10, within three months of the effective date of cancellation or the date of order of cancellation, whichever is later.