"This assessment is deemed to be served on the addressee under applicable law ten days from the date this assessment was mailed by the tax administrator as shown on the assessment, and all periods within which an appeal may be filed apply from and after that date."
Unless the mailing is returned because of an undeliverable address, the mailing of that information is prima facie evidence that delivery of the assessment was completed ten days after the tax administrator sent the assessment by ordinary mail and that the assessment was served.
If the ordinary mail is subsequently returned because of an undeliverable address, the tax administrator shall proceed under division (B)(1)(a) of this section. A person may challenge the presumption of delivery and service under this division in accordance with division (C) of this section.
R.C. § 718.18