What must I do now regarding the many days of unobserved Ramadan fasting that I did not make up due to my ignorance of the obligation to make up days of menstruation, especially since I used to fast six days of Shawwal without the intention of making up (the missed days), knowing that intention is a condition, and what is the ruling on this matter according to the Hanbali and Hanafi schools of thought?

The Hanbalis and Hanafis stipulate the intention (niyyah (definition)) for fasting to make up for missed Ramadan (definition) days, and that this intention must be made the night before. The Hanafis require this because the time for making up the fast is not specifically designated, while the Hanbalis require it for every obligatory fast. Accordingly, one's obligation is not discharged except by making up those days, as it is a debt that must be repaid. According to the Hanbalis, a fidyah (definition) (expiatory feeding) of one poor person's meal is obligatory for each day whose make-up was delayed until after the subsequent Ramadan. As for the Shafi'is, they do not consider the fidyah obligatory if one was unaware of the impermissibility of delaying the make-up fast. If the questioner does not know the exact number of days, she must investigate and make up what she believes will absolve her responsibility.