What should the questioner do after more than 3 years have passed since she ate in Ramadan while menstruating, without remembering the quantity of food?

The question is unclear, but considering the most probable interpretations, if the questioner means that she broke her fast in Ramadan and does not know the number of days she missed, then she must make up the days she believes she missed. She must also pay expiation for delaying the make-up if the delay was without a valid excuse.