Any order made under § 7-212 shall be in writing and may be served personally upon the owner or occupant of the premises or by leaving it with any person in charge of the premises or if the premises are unoccupied and the owner is a nonresident of the city, then by mailing a copy to the owner’s last known post office address. One notice to either the occupant or owner shall be sufficient. The Fire Department shall keep a record of and copies of all such orders and notices and shall follow up such notices at the expiration of the time for compliance therewith and when complied with make proper entry, and if not complied with, file complaint with the Municipal Court against the property owner and/or occupant.