Is he who forced me to sign a mutual termination of contract sinful, and am I entitled to claim the remaining period of the contract?

Contentious issues between contracting parties cannot be resolved remotely through a fatwa. Such matters are settled by the judiciary or an arbitrator agreed upon by both parties. A rental (ijarah) is a binding contract, and neither party has the right to unilaterally terminate it before its term expires, except for a valid excuse. If the tenant terminates it without a valid excuse and without the landlord's consent, the landlord has the right to the rent for the remaining period.