Is it permissible to purchase a phone in installments at a price higher than its cash value, provided that this is conditional upon subscribing to a telecommunications service for two years, which cannot be separated from the purchase contract?

There is no objection to purchasing a phone in installments while benefiting from free services during the installment period. Selling in installments with an increase in price is permissible and has been affirmed by the Islamic Fiqh Academy. If the free services are a gift from the company, there is no objection to promotional gifts attached to the sale. And if the company sells the phone and the service as a single package, this is permissible according to the preponderant opinion, which is the madhhab of the Hanbalis and the choice of Shaykh al-Islam Ibn Taymiyyah, where it is permissible to combine sale and lease in one contract.