Purpose-This paper aims to demonstrate that online complainants' reactions to a company's service recovery attempts (webcare) can significantly vary across two different types of dissatisfied customers ("vindictives" vs "constructives"), who have dramatically diverging complaint goal orientations. Design/methodology/approach-Online multi-country survey among 812 adult consumers who recently had a dissatisfying brand experience and turned to a marketer-generated social media site to voice an online complaint for achieving their ultimate complaining goals. Scenario-based online experiment for cross-validating the survey findings. Findings-Results suggest that "vindictive complainants"driven dominantly by brand-adverse motivesare immune to any form of webcare, while "constructive complainants"interested in restoring the customer-brand relationshipreact more sensitively. For the latter, "no-responses" often trigger detrimental brand-related reactions (e.g. unfavorable brand image), whereas "defensive responses" are likely to stimulate postwebcare negative word-of-mouth. Research limitations/implications-This research identifies the gains and harms of (un-)desired webcare. By doing so, it not only sheds light on the circumstances when marketers have to fear negative effects (e.g. negative word-of-mouth) but also provides insights into the conditions when such effects are unlikely. While the findings of the cross-sectional survey are validated with an online experiment, findings should be interpreted with care as other complaining contexts should be further investigated. Practical implications-Marketers have to expect a serious "backfiring effect" from an unexpected source, namely, consumers who were initially benevolent toward the involved brand but who received an inappropriate response. Originality/value-This research is one of the first research studies that enables marketers to identify situations when webcare is likely to backfire on the brand after a service failure.