Suspension of GST registration restricts filings and supplies pending resolution of alleged non compliance and cancellation proceedings. Voluntary cancellation is available where business is discontinued, transferred, amalgamated, demerged, or its constitution changes, or where a voluntarily registered person is no longer liable. A proper officer may cancel registration for defined malpractices and non compliances after opportunity to be heard, and may suspend registration during proceedings under rule 21A. Suspension prevents filing returns, making taxable supplies and claiming refunds; suspension may be revoked on completion of proceedings or on compliance with prescribed conditions. Cancellation does not relieve pre cancellation tax liabilities.