Importer delinquent on CBP bills: 10 working days, then 7501 with duties before release

An importer with merchandise currently in CBP custody at the Port of Laredo is substantially delinquent in the payment of several bills for additional duties owed. The Port Director of Laredo has provided written notice to the importer, specifying that if all delinquent bills are not paid within _______ working days, importations of his merchandise will be denied release until CBP Form _______ or its electronic equivalent is filed with the estimated duties attached.