Does a sin fall away if I pay money to Quran memorization charities as an act of charity after my friend refused to return the money I took from her intentionally and unintentionally?

Repentance from injustices requires restoring rights to their owners or seeking their forgiveness. Donating these rights as charity on behalf of their owners is not sufficient, except when one is unable to deliver them to the rightful owners. Therefore, regarding the amounts that were not recorded due to oversight and for which the owner has forgiven you, there is nothing due from you. As for the amounts that were not recorded intentionally, they must be returned to their owner by any means. Charity does not absolve you as long as you are able to return them, because her apparent forgiveness applies to what was an oversight, not to what was intentional.