Is a company entitled to exchange goods by taking them at their old price and selling the new items at their new price, which leads to the buyer's capital loss?

It is impermissible to agree with the seller that the buyer will return the merchandise if it is not sold, due to the presence of Jahalah (uncertainty) and Gharar (definition) (excessive risk), which is known as "Tasreef sale" (sale with a return condition). This condition is فاسد (invalid). The jurists have differed on whether the sale itself becomes invalid due to this condition. The Hanafi and Shafi'i schools of thought consider the sale to be invalid.

This condition must be cancelled. If the buyer still possesses unsold items, he can offer them to the seller for return. If the seller agrees, this is a permissible Iqalah (cancellation of sale), and he will be rewarded for it, as the Messenger of Allah (peace be upon him) said: "Whoever cancels the sale for a Muslim, Allah will cancel his stumble."

The seller returns the original price to the buyer. It is permissible for the buyer to take other merchandise, and the returned item can be calculated at its original price, or less, or more, with the consent of both parties. This is because Iqalah is permissible for the same price, or less, or more, according to the preponderant opinion. There is no harm in calculating the returned goods at the old price and the newly purchased goods at the new price, provided that the seller's acceptance of the return is by his free consent, not based on the invalid condition.