What is the ruling on selling a product over the phone while deluding the customer into believing there is a discount, by mentioning a higher price (50) and then offering it at a lower price (30) as if it were a reduced price, when in reality it is the original price?

Deceiving the buyer by telling him that a product's price has been reduced when it has not is an outright and forbidden lie. Lying in transactions is even more severe, and what the seller earns through lying will have no blessing in it and will bring him harm. The Messenger of Allah, peace and blessings be upon him, said: "The two parties to a transaction have the option [to annul it] as long as they have not parted. If they are truthful and make clear, they will be blessed in their transaction. And if they conceal and lie, the blessing of their transaction will be effaced." Thus, truthfulness and clarity bring blessing, while lying and concealment efface it. This action indicates a deficiency in faith, for a Muslim does not truly believe until he loves for his brother what he loves for himself. Let whoever commits such an act beware, for Allah's punishment lies in wait for him.