Is selling Instagram usernames, which are obtained through indirect means such as using programs (checker, turbo) that might acquire usernames owned by other individuals who paid for them, or by defrauding technical support by falsely claiming ownership of accounts, forbidden, and consequently, is the resulting gain unlawful?

For the sale of usernames to be permissible, it must not infringe upon the rights of others. Therefore, it is impermissible to acquire them through deceit, as they possess considerable value, and their owners have a greater right to them due to their prior acquisition, even if they did not pay money for them. This is supported by Hadiths that prohibit cheating, deception, and infringing upon the rights of others, such as: "Whoever precedes to a permissible thing has a greater right to it," "The wealth of a Muslim person is not lawful unless given with the full consent of his soul," "Whoever cheats us is not one of us," and "Cunning, deception, and betrayal are in the Fire." It is obligatory to seek what is lawful in earning, because provision is decreed, as stated in the Hadith: "Indeed, the Holy Spirit inspired in my heart that no soul shall die until it fulfills its term and receives its full provision. So, fear Allah and be graceful in seeking it."