Non-transition of CENVAT credit prohibits use of inadmissible or blocked transitional credits and mandates recovery with interest and penalty. Registered persons must not utilize in the electronic credit ledger any CENVAT credit adjudicated as inadmissible ('disputed credit') or amounts ineligible under the Act ('blocked credit'); unauthorized utilization will be recovered with interest and penalty. If such transitional credit exceeds the prescribed threshold, taxpayers must furnish an undertaking to the jurisdictional Central Government officer that the credit has not been and will not be utilized.