How to prove that I didn't hack?

Until recently, I was a supporter on a specific Minecraft server. I played KnockbackFFA and got kicked out and got a ban. The reason is apparently hacking. (Velocity - No Knockback) They have a replay, they are not allowed to show it because it is internal to the team, but it can't be somehow. Of course I didn't hack, but how can I prove that I didn't hack now?

Do you have a picture of it? If not, that's stupid. I think only persuasion helps.