In the case of an unjust suspension (or at least what a user considers to be an unjust suspension), it seems that better way than to bring this up on meta would be contact the SE team using the [contact form](http://mathoverflow.net/contact) or by writing an email to [email protected].

See, for example,  an answer to the meta.SO question: http://meta.stackexchange.com/questions/165359/where-i-can-complain-about-an-unfair-account-suspension/165360#165360. This solution was also suggested to you in a [similar discussion on meta.MSE](https://math.meta.stackexchange.com/questions/11158/having-been-flagged-many-times-can-be-a-reason-for-the-suspension#comment42293_11160).

EDIT: As François G. Dorais points out in [his comment below](https://meta.mathoverflow.net/questions/1066/protest-for-my-account-suspension#comment4779_1068), another way to dispute a suspension is to [contact the MathOverflow moderators](https://meta.mathoverflow.net/questions/833/who-are-the-mathoverflow-moderators).