Write a forum PM to CG_Leviathan and include evidence in form of screenshots (e.g., his fleet roster and the superior roster of someone who was cheated out of his rank by him). It might take a while for CG to look into this, but it's more effective than the ingame report button. Mention your ally code too so they can find your shard.
PS: It might be counterproductive to explain how cheating is possible. Or at least without mentioning that using a hacked anything is a great way to have one's account and RL information hacked and stolen, including payment information.
