If I order a $30000 shipment of fish and you deliver them 2 days late, I have all legal rights to refuse the shipment and require the full amount back + my losses or lost profit (in the amount I can prove in court) for not having the fish back when you agreed to deliver them.

You don't need to be called an exchange or sell currencies in order to be financially liable for delays; and the more perishable/volatile the product is, the larger the possible liabilities.