With the increased dynamics of modern life, the efficiency and reliability of everyday services is emerging to be a fundamental concern. On the other hand, modern telecommunication technologies, like wireless Internet access, are penetrating all segments of our life. However, many every day activities and services still do not fully exploit new technologies. We propose an approach that enables increased deployment of E-commerce concepts in the fields where their usage was either small or negligible. Moreover, in the scope of the same concept, we introduce prioritization of clients in services where it was not commonly present to date. A solution for enhanced communication interface between service provider and customers is developed. As a case study, the system is designed and optimized for an implementation in a fast-food chain. The proposed solution is aiming at increasing of quality of service for customers, and at the same time increasing the operational efficiency of the provider. The main idea behind this approach is to enable customers to use their mobile devices, such as cell phones or PDAs, for browsing offered services or goods, viewing current service conditions and placing orders. We will detail mathematical model underneath and describe the implementation on both server and client side.