How do I handle out-of-stock complaints?

As an e-commerce store owner, I'm struggling with managing customer frustration when products go out of stock. Customers often get upset when they find a product they want is unavailable, and I need a comprehensive strategy to handle these situations professionally and maintain customer goodwill. I want to understand the best practices for communicating stock issues, retaining customer interest, and potentially preventing future disappointment. What are the most effective ways to manage out-of-stock scenarios that can actually turn a potentially negative experience into a positive customer interaction?