As for the transaction itself, it will be valid, however, since it would be unethical by it going against the spirit of a final and conclusive sale as promoted by the Sharia, one should avoid doing so. We should try our best to align ourselves with Sharia based ethics so that there is baraka in our life, time, and wealth.

And Allah knows best. 

Mufti Farhan ul Haq
Assistant Mufti, Darul Iftaa Chicago

Reviewed and approved with comments

A person should put themselves in the shoes of the seller and consider would they would be fine with a customer buying their product with the intention of using it, taking its benefit, and then returning the used product afterward and demanding a full refund, or would they consider it as unethical, dishonest, and an unfair advantage of a return policy. Additionally when the seller refunds to the customer, they have to refund the full amount, even if they incurred credit card or other transaction fees. So, not only does the seller now have a returned, used product that loses market value, but they also lost money on the transaction (plus any additional costs for repackaging it). It should be clear that this is not in line with the ethics that we learn from the sunnah.

Mufti Abrar Mirza
Head Mufti, Darul Iftaa Chicago