What, according to Islamic law, should I do regarding family problems with my wife's family, who refuse the return of my wife and daughter except under financial conditions, and my wife follows their opinion despite knowing the truth?

A wife is not permitted to leave her husband's home without his permission, nor are her family allowed to incite her to do so, as this constitutes disobedience from the wife towards her husband and an act of 'nushuz' (rebellion). If the wife has left the marital home due to the husband's inability to provide maintenance (nafaqah), the majority of jurists hold that this is a valid justification for separation between them if the wife requests it. For the wife to return, the husband should mend his relationship with Allah, supplicate to Him, come to an understanding with the wife's family, involve religious figures as mediators, and then bring the matter before the judiciary.