Is all money obtained from services purchased with a stolen Visa card considered unlawful gain, and if not, what is the amount that must be disposed of and how?

Scholars have differed regarding the profit generated from money taken unjustly. Sheikh al-Islam Ibn Taymiyyah preferred the view that the profit should be equally shared between the one who took it and the one from whom it was taken, similar to a Mudarabah (definition) partnership.

Based on this preferred view, what you are entitled to from the profit generated by those websites is only half. As for the other half, you must return it to the cardholder if possible. If the cardholder cannot be reached, the stolen principal and half of the profit must be spent on the welfare of Muslims (such as aiding the poor and needy, and building hospitals and schools). If the owner of the money appears later, they are given the choice to either approve the charity or have the amount returned to them.

Among the conditions for repentance are: regretting the sin, resolving not to return to it, and frequently seeking forgiveness and performing righteous deeds.