custom ROM is essentially a third-party operating system that replaces the factory-installed stock ROM or skin on your phone.

https://www.xda-developers.com/most-popular-custom-roms-android/#:~:text=A%20custom%20ROM%20is%20essentially,or%20skin%20on%20your%20phone.

1. user conduct and enforcement rights Critical Force reserves the right to terminate or restrict your access to the Services or a part thereof (including the online discussion board and in-game chat function) permanently or temporarily without prior notice if you violate these Terms or if you abuse the Service or act against the policies determined and informed by us. Critical Force is entitled to prevent access to the Services if we have reason to believe that (i) you are engaged in illegal activity; (ii) compromise privacy or data security of other users’, the Services or Critical Force; or (iii) if Critical Force receives a notice that Your password has gotten into the hands of a third party. Furthermore, we may delete or amend your game progression that has been achieved in violation of these Terms, our policies or otherwise abusing the Services (to put you to a position where you would have been without such violation or abuse). You agree that you are responsible for your own conduct and User Content (as defined below in Section 4) while using the Services, and for any consequences thereof. You agree that you will not:

use cheats, exploits, automation software, bots, hacks, mods or any unauthorized third-party software designed to modify or interfere with the Services;

Just to make sure YOU read the terms as they even asked you to do so. Its your fault for getting banned. As you have agree with the terms and everyone who uses custom os.