To report allegations of checkuser or oversight misconduct, please contact the Arbitration Committee by email at <arbcom-enwikimedia.org> (or, if your account has email enabled, you may use Special:EmailUser/Arbitration Committee). Include concise information about what action was performed, who did so, approximately when it happened, and why you believe the actions to be policy violations.
In some cases, you may contact the Ombuds Commission instead of or in addition to the Arbitration Committee. For more information, including contact details and when to report violations, please see their page on Meta wiki.