No land shall be occupied or used and no building or other structure erected, altered, extended, enlarged or, if a nonconforming use, restored, occupied, used, or changed in use until a certificate of occupancy has been issued by the Code Enforcement Officer stating that the building, other structure or proposed use thereof complies with the provisions of this chapter. Vacated existing commercial properties may not be used or occupied until a certificate has been issued to ensure that the new use or occupancy is permitted.