What is the ruling on debt resulting from the price of something unlawful, such as alcohol or hashish, and what must one who repents from this act do concerning this debt?

This person is congratulated on their repentance. They must dispose of the hashish if it is still present, or donate its value to charitable causes if they have consumed it. It is not permissible to return hashish or to pay compensation for it. This is the view held by Sheikh al-Islam Ibn Taymiyyah.