(1) When dispute crosses all the limits between husband and wife and it becomes difficult for them to maintain the guidelines set by Almighty Allah, then the woman can demand for talaq or khula. It is not lawful for woman to demand for talaq or khula unnecessarily.
(2) If husband does not pay conjugal rights and keeps the woman suspended neither divorces her nor agrees for khula, such woman can take her case to any sharai punchayat or Darul Qaza. After investigating the case, if they consider that revoking the nikah is suitable then they can revoke the nikah.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband