Electric Vehicles (EVs) are gradually becoming more attractive, as they offer economically viable and environmentally friendly transportation solutions when compared to their gas-powered counterparts. This trend requires wide deployment of fast charging stations to extend EV driving ranges. However, the operation of such facilities could become a bottleneck, as the power demand from the grid, especially during the peak hours, may disrupt its reliability. Hence, in this work, we provide an incentive-based control mechanism to shift the peak-hour EV load to off-peak hours. The pricing scheme enables the charging station operator to provide Quality-of-Service (QoS) guarantees to its customers. We identify two customer classes. The first class includes charging station users, which are pass-by customers that receive a one-time service from the station. The EV users prefer to get the service either upon arrival or in the next time period. They take their own decision by taking the risk of being blocked, which serves as the main performance metric. On the other hand, the second class of customers are charging station subscribers, which have agreements with the station operator and receive discounted prices. Hence, the station operator guarantees to serve the EV subscribers within a specific time window that is determined in their contracts. Therefore, the average waiting time becomes the primary QoS metric. Our results indicate that with the proposed framework, more customers can be served using the same amount of grid resources and the peak demand can be shifted to other off peak periods, while ensuring grid reliability.