What is the ruling on subscribing to a monthly phone service for a fixed amount for a specific call duration, with the full amount being paid even if no calls are made, and additional fees being paid for extra minutes?

There is no objection to subscribing to a telecommunication service that specifies a certain period for the benefit to be utilized, after which, if it is not utilized, it is forfeited by its owner. The rental fee becomes due upon enabling the lessee to use the benefit. If the lessee utilizes it or the period expires without any impediment, the fee is settled. The company has the right to charge for extra minutes, by analogy with other benefits such as renting a house.