What is the ruling on a penalty clause when a customer cancels their subscription before the agreed-upon period, regardless of whether the subscription includes only a phone line or a line and a device?

The annual telecommunications contract is a legally permissible lease (ijarah (definition)) contract for a service, and it is a binding contract that neither party may unilaterally terminate except with the consent of the other party. The penalty clause upon termination is permissible and valid, and it does not include moral or emotional damages. It is preferable to release the party wishing to terminate the contract without charge. There is no objection to obliging the customer to pay the remaining installments for the mobile device upon termination of the subscription, provided that there is no increase over the agreed-upon price.