here is an excerpt from Texas statutes:
By that definition, I would suggest that at least when the payment was actually transferred to the creditor would be the date of acrual. If you sent a subsequent check, you apparently had dealing more recently than that date even so I would say they filed within the SoL.(c) A person must bring suit against his partner for a settlement of partnership accounts, and must bring an action on an open or stated account, or on a mutual and current account concerning the trade of merchandise between merchants or their agents or factors, not later than four years after the day that the cause of action accrues. For purposes of this subsection, the cause of action accrues on the day that the dealings in which the parties were interested together cease.

