Hiring/Renting: Being Cheated in a Rental Agreement
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 2218
If a lessor or a lessee realises that he has been cheated, in the event that at the time of concluding the rental agreement he was not aware of being cheated, he can annul the rental agreement as per the details mentioned in Ruling 2134. However, if they had stipulated a condition within the rental agreement that even if they are cheated they do not reserve the right to annul the transaction, then they cannot annul the rental agreement.
-Ayatullah Sistani, Practical Laws of Islam, Hiring/Renting (Ijarah)