If you have an issue with a vendor, find someone to help you resolve your issue. Make sure that person understands how their service failed to meet your expectations. But don't stop there. Send a letter to a more senior manager with a summary of the incident. A written note is especially relevant to recognize a satisfactory resolution. Doing so is an opportunity to generate goodwill by recognizing the person who helped you experience a positive result. Don't waste time complaining to someone who cannot resolve the situation. Seek out someone who can.