In this context, I have in mind a typical business transaction, not a complex contract with explicit terms and so forth.
Suppose a business receives an order from a customer, and payment for the order is received in whole or part, but the business has issues with delivering on it's end because of circumstances outside of it's control, like a bad receiving address, or a bad email (often used as the customer's gateway to access virtual products). The business surely has a duty to attempt to contact the customer to complete the order, but what if the customer proves unreachable based on the means available to the company (phone, email, mail, etc.)? In other words, you call, but they never call back, or your only contact method is email, but it bounces back.
If the order was placed via a credit card, the business can easily issue a refund despite the inability to contact the customer. Even with payment by check, the business can send out a refund check to a mail address, assuming there's been no evidence of a bad receiving address. The question is, does this business have a legal duty to any such actions? I know credit card companies will typically not process refunds for transactions older than 60 days, so is there a time limitation after which the company may assume the order "complete" and retain the funds?
I'm concerned only with US Law. Specifically, the business I have in mind is in the State of Idaho, but most customers are not Idaho residents.