What is the ruling of Islamic law and what should I do regarding a dispute between me and my wife, and her family's demand that I sign a dowry list for an amount we never originally agreed upon, as a condition for furnishing the two apartments and her return?

If a wife willingly grants herself to her husband, her guardian has no right to withhold her from him, even if the husband has not paid the prompt dower. Therefore, your father-in-law's action is unwarranted, and you have the right to demand that he surrender your wife to you. If he refuses, you may refer the matter to the concerned authorities. If there is a specific obligation due from you to your wife, you must fulfill it and not procrastinate, as the Prophet (peace be upon him) said: "The procrastination of the rich is injustice." It is recommended that righteous and conciliatory individuals intervene to resolve disputes.