What is the ruling of swapping individual units of a packaged item in the store before purchasing?
In the Name of Allah, the Most Merciful and Compassionate
Taking items out of a packaged set and exchanging them for another is impermissible as this entails deception to the seller, even if the item exchanged is cheaper than the original – for the following reason:
Mutual Consent In Business Transactions
The basis of business transactions is mutual consent (taradi). Allah Most High says, “O believers! Do not devour one another’s wealth illegally, but rather trade by mutual consent. And do not kill ˹each other or˺ yourself. Surely Allah is ever Merciful to you.” [Qur’an; 04:29]
For this, any transaction done in a manner that actually or effectively causes one of the contracting parties to be discontent with the sale is corrupt and sinful. [Maydani/Quduri, al-Lubab fi Sharh al-Kitab]
This applies to hiding faults in the merchandise, extreme overpricing, insufficient description of the merchandise, not mentioning a price, etc…
Thus by switching the items of a set, the seller is now unknowingly selling an item for possibly a different price than they would expect.
However, since you are not certain that your mother switched the clothing, then act on the following:
(1) Ask her. If she admits to switching the items, then you must return the item or its monetary value to the store. Note you don’t need to inform them of the reason. [Ibn ‘Abidin, Radd al-Muhtar]
(2) Use your judgment. If you are reasonably sure that your mother swapped the items, then apply the above solution.
However, if you are not reasonably sure that you have no proof that your mother switched the clothing, it is not obligatory to return the clothing or its monetary value.
Hope this helps
Allah knows best
[Shaykh] Yusuf Weltch
Checked and Approved by Shaykh Faraz Rabbani