One of the main strategies in oil industries management is the evaluation of the relationships between the customers and employees. To do so, the interpretive paradigm, the qualitative approach, and the Grounded Theory Approach have been used. As for the qualitative approach, snowball sampling has been used, and the latent content analysis technique has been used to analyze the in-depth reviews, helping to code and identify the employees’ cognitive appraisal indices. Also, as for the quantitative approach, simple random sampling was used, with a structural equation model used for data analysis. The results and findings of the study indicate that the top managers in Iran Petroleum Products Distribution Company, especially those in the Human Resource Development, Commercial, and Research & Technology sections, can use the model extracted in the current study as well as the suggestions provided, to pay more attention to the mental health of the Frontlie Employees (FLEs). They can also use the results to know how the employees deal with the customers’ aggression and abuse. Hence, the current study can be useful for the oil industries researchers.