Ohio Rev. Code § 2305.07

(A) Except as provided in sections 126.301 and 1302.98 of the Revised Code, an action upon a contract not in writing, express or implied, shall be brought within four years after the cause of action accrued.

(B) An action upon a liability created by statute other than a forfeiture or penalty shall be brought within six years after the cause of action accrued.

(C) Except as provided in sections 1303.16, 1345.10, and 2305.04 of the Revised Code, and notwithstanding divisions (A) and (B) of this section, section 1302.98, and division (B) of section 2305.03 of the Revised Code, an action arising out of a consumer transaction incurred primarily for personal, family, or household purposes, based upon any contract, agreement, obligation, liability, or promise, express or implied, including an account stated, whether or not reduced to writing or signed by the party to be charged by that transaction, shall be commenced within six years after the cause of action accrued. For purposes of this division, a cause of action accrues thirty calendar days after the date of the last charge or payment by, or on behalf of, the consumer, whichever is later.