Will Allah forgive one who was in a dispute with the official who wronged her, after she forgave her and repented, or does she bear a sin that requires expiation?

If the matter is as you described, and there was no error or transgression on your part, but rather you only clarified the injustice that befell you, then there is no blame upon you. It is hoped that you will be among those whom Allah forgives on the night of the 15th of Sha'ban, and that you will attain the reward for pardoning and forgiving those who wronged and mistreated you.