What is the ruling of the Sharia on living in an apartment whose rent is paid by another person using his card without the knowledge of the leasing association, knowing that the association's regulations prohibit this procedure and require the apartment to be handed over to them upon departure?

Muslims must adhere to the conditions agreed upon in their contracts unless they violate Sharia. If the landlord stipulates that the tenant must inhabit the property himself, then the tenant is not permitted to sublet it to others. If the tenant is unable to benefit from the leased property due to travel or illness, he may terminate the lease. If the lease contract is valid, and the tenant travels and pays the full rent, and he is not refunded for the period he did not inhabit the property, then he may sublet it for a period to recover his right, and then hand over the apartment to the association.