With the increasing usage of platforms such as Facebook, understanding customer complaint behaviour (CCB) in the context of the social media is imperative for any businesses. Of the two billion users on Facebook, more than half of its users have shared their product-related experiences with others on the platform (Logan, 2014). This paper aims to explore CCB in the context of social media in regards to customers' unfavourable buying experiences in the retail sector. A qualitative research approach and 12 in-depth interviews were conducted. The findings indicate that the respondents' initial contact with the retailer directly resulted in service recovery failures and undesirable outcomes. Such double deviation then leads to frustration and uncertainty of the situation, which furthermore led to the respondents' need to voice their complaint by sharing their unfavourable experiences on Facebook. The main reasons for the respondents to voice their complaints on the platform is to vent frustration, to share their unfavourable experiences, a need to be seen, understood and respected, to seek revenge by damaging the retailer's reputation as well as offering the retailer a chance to improve. A proper way to manage complaints, in which frontline employees can solve the problem before the customers feel the needs to turn to the social media, is crucial. However, once the complaints is voiced on Facebook, it is imperative to respond to the complaints and acknowledge the problem rather than ignoring the situation.Since the study requires reflections and opinions of the respondents, a qualitative methodology approach and semi-structured interviews were applied. While customers may voice both favourable and unfavourable experiences on the social media as part of electronic word-ofmouth (e-WOM), this paper focuses on the latter such as customer complaints. In addition, the study concentrates on the respondents' perceptions and their point-of-view of the given situation that they have experienced.