Social media offer an unprecedented opportunity for companies to interact more closely with customers and market their products and services. But social media also present reputational risks as negative word-of-mouth can spread more quickly and widely through these platforms than ever before. This study investigates how companies respond to customer complaints on Twitter. We propose an innovative mixed methods approach (i) to identify the key features that mark the styles used by a sample of companies in their replies to customers and (ii) to determine the most effective strategies for responding to complaints. Our results reveal that an affective style, expressed through devices such as stance markers, emphatics, and amplifiers, elicits the most positive response from complainants, regardless of the formality of the message. The study advances our understanding of the features and effects of corporate social media discourse. It also provides business communication practitioners with linguistically grounded insights that can inform the development of appropriate strategies for dealing with negative word-of-mouth online.