Anyways, I am assuming you were banned by Sentinel (The Anti Cheat). You can appeal on the site, just like Pingu_ said (
https://appeals.cubecraft.net). If you appealed, and it did get denied, then you can talk to CrazymanJR (the Anti Cheat developer) privately on discord (CrazymanJR#4742). You can join the CubeCraft discord, using this link:
https://discord.gg/cubecraft.You can tell him
what you were doing, and
where were you BEFORE you got banned by Sentinel. Just a reminder, you would have to be patient, because you are not the only player who was banned by the Anti-Cheat unfairly, and would like to get unbanned.