Dealing in business transaction
Hakim bin Hizam (radi Allahu anhu) reported that the Messenger of Allah (sal Allahu alaihi wa sallam) said, “Both parties in a business transaction have a right to annul it so long as they have not separated; and if they tell the truth and make everything clear to each other (i.e., the seller and the buyer speak the truth, the seller with regard to what is purchased, and the buyer with regard to the money) they will be blessed in their transaction, but if they conceal anything and lie, the blessing on their transaction will be eliminated.”
[Sahih al-Bukhari and Muslim]
Here, the two persons engaged in business are the seller and buyer.
The word ‘right’ here means that so far both of them are present at the spot where business is being transacted they have a right to cancel their bargain. In other words, even after the mutual acceptance of the terms of the bargain so long as they are present at the spot they are entitled to cancel the deal until the time they separate from each other.
Generally, people do not think it permissible to cancel the bargain after it has been settled even though both parties are present there, but this is not correct. Their view is contradicted by the Hadith.
Truthfulness is a means of blessings in the business while falsehood and hiding of any defect of the merchandise detract from its blessings.
And Allah Knows Best!