The use of swgoh.gg will not get you banned, as swgoh.gg is not 3rd party software that has an effect on gameplay. Rather, it is a useful tool that can pull your game information, allowing you to look at your mods, see what gear pieces you need, see character abilities, and other such information.
3rd party software that has an effect on gameplay, such as hacks or cheats, that allow players an advantage in game is banned. If you suspect someone of cheating, please send a forum PM to @CG_Leviathan or @CG_LucifersDaddy with details on why you think someone is cheating, your ally code and the name of the suspected cheater.