What should the accused seditionist, whose reputation has been tarnished, do if what was said about him is untrue?

The entire affair of the believer is good, for he alternates between gratitude and patience, and in both there is reward. Indeed, the best of creation, who are the Messengers, were slandered, even the Prophet, may Allah bless him and grant him peace, was accused of sorcery and madness, and the hypocrites slandered his honor. Yet, he persevered, sought his reward from Allah, and entrusted his affair to Allah.

You should be patient and seek your reward from Allah, for that expiates sins. You are also allowed to defend yourself, prove your innocence, and belie those who accused you, as this is not considered forbidden backbiting. If you are able to confront those who accused you, advise them, and warn them of Allah, that is better, or you can send someone to do so.

Avoid situations that raise suspicion, and you must be patient and persistent in supplication for Allah to relieve you.