What is the Sharia ruling on taking money from a person who paid for an electronic product with the intention of stealing or leaking it, given that the seller has not yet sent the product?

It is not permissible to take a Muslim's money without his willing consent, due to the Almighty's saying: "O you who have believed, do not consume one another's property unlawfully but [only] that your consuming be [involving] trade [carried out] by mutual consent from among you." And due to the Prophet's (peace and blessings be upon him) saying: "The property of a Muslim is not lawful except with his willing consent," and "The whole of a Muslim is inviolable for another Muslim: his blood, his property, and his honor." Whoever unlawfully seizes a Muslim's property will meet Allah while He is angry with him. Therefore, the money must be returned to its owner, and one must seek forgiveness.