Question 7: A sixty year old lady was ignorant of the rulings of menstruation for many years. She did not make up for the days she had not fasted in Ramadaan because she thought these days were not to be made up for as she had heard from some common people.
A: This lady has to make Tawbah (repentance to Allaah) from doing so because she did not ask people who are knowledgeable of the rulings of Islaam. She should also make up the number of days that she thinks were most probably missed. Moreover, she has to offer a Kaffarah (expiation)… read more here.