This study analyzes consumer dissatisfaction in Brazil through 7.4 million complaints filed between 2016 and 2023 on Consumidor.gov.br related to purchases in physical and online stores. Descriptive statistics and chi-square tests reveal key demographics and complaint features. All null hypothesis was rejected. Men aged 31-40 from the Southeast, particularly São Paulo, dominate complaints. Financial services, telecommunications, and transportation top complaint categories. Most complaints were filed in 2021 and successfully resolved on the platform. Notably, a significant portion of consumers contested their complaints, highlighting potential post-purchase dissatisfaction beyond initial resolutions. This study reveals that exist variance concerning consumer expectations and the characteristic of the product or service brought by the respondent company. By understanding causes of dissatisfaction, it becomes possible to seek developments in the products and services offered to elevate overall post-purchase satisfaction levels.