If the watch was purchased using Stripe as the payment method, and the watch is not available, the seller will need to reimburse the buyer. However, it's important to note that Stripe fees, which are incurred during the initial transaction, are typically not reimbursed by Stripe. Therefore, the seller will bear the responsibility of covering those fees. It's recommended for sellers to familiarize themselves with Stripe's terms and conditions regarding refunds and fees to ensure a clear understanding of the financial implications in such situations.