What is the ruling on selling via television, where the buyer does not have the right to refuse the sale after the representative leaves with the product?

Buying and selling are based on mutual consent, and every sale concluded with consent is permissible unless Allah and His Messenger have forbidden it. Since consent can be obtained via television or modern means, contemporary scholars have permitted the conclusion of contracts through these means, by analogy with the permissibility of contracting through letters and writing. If the sold item is found to be as described and free of defects, the buyer has no right to reject it except through cancellation (iqalah). However, if it is found to have a defect of which he was unaware, he has the right to return it.