What is the ruling on fasting for past years that were not fully observed, due to not remembering the number of days or their overlapping with menstrual days, while being unable to feed a poor person?

If you intentionally broke your fast in Ramadan after reaching puberty, you have committed a great sin, and you must repent sincerely and make up for all the days you missed. You must hasten to make up for them immediately, unless doing so would cause you harm. However, if your not fasting was due to ignorance of the ruling, then, according to many scholars, you are not required to make up for those days. The fidyah (expiatory feeding) of feeding one poor person for each day is due if you delayed making up the fast until after the next Ramadan, unless you were unaware of the prohibition of delaying, in which case nothing is required of you. If you are unable to pay the fidyah, it remains a debt upon you until you are able to pay it.