I believe their account ban system works similarly to how we authenticate accounts here. You just need to change your HWID, use a new IP (probably) and a new account, and you should be good to go. I'm not entirely sure how you can change your HWID but you can probably just google "fortnite HWID change program" to find something that helps you there, as Fortnite also uses HWID bans to ban computers from their software.