Does a person get back what they lost if they say: "Indeed, He is able to bring him back" 200 times?

That has not been authentically reported in the Book of Allah or the Sunnah of the Prophet, peace be upon him, and it is not among the ordinary means for recovering lost items. This is considered using the Qur'an for something other than what it was revealed for, and specifying a number is a matter of divine injunction that cannot be known by intellect. Therefore, using it is an innovation, and the Prophet, peace be upon him, said: "Whoever introduces into this matter of ours that which is not from it, will have it rejected."