Whatever you do, resist the urge to act like an ostrich during a crisis. Putting your head in the sand when a customer is unhappy won't stop them from telling others about their bad experience. Before this wreaks havoc on your business, resolve the problem by doing your homework. Go the extra mile to figure out why your client is frustrated and go the distance to make things right. And don't get your feathers ruffled even if you have to spend some cash to correct the issue - it'll be worth it in the end to restore your customer's peace of mind and make them happy as a lark.