If such property is not claimed by the owner or the owner’s agent within 12 months after its receipt by such storage company, it may be sold by such company at public auction. Before making sale three weeks’ published and posted notice thereof, describing the property and specifying the time and place of sale, shall be given. The publication of such notice shall also be made in a newspaper published at the county seat of the county where the sale is to be made, and a copy thereof shall be mailed to the owner, if the owner’s address is known, or, with reasonable diligence, can be ascertained.