Buying and Selling: Immediate Annulment After Discovering a Defect
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 2142
If after a transaction a person realises that the item has a defect, in the event that he wishes to annul the transaction, he must do so immediately. If he delays in annulling for more than a normal amount of time – taking into account the type of case it is – he cannot annul the transaction.
-Ayatullah Sistani, Practical Laws of Islam, Buying and Selling