Answer:
(Fatwa: 592/552=L/1429)
If the husband confesses then the three talaqs pronounced on phone took place. Being in menstruation period does not prevent talaq from taking place. When talaq is pronounced there is no need to give it in writing. A later written talaq may serve as proof in case of necessity.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband
