Can´t Sign Up, work domain used to have Office365 tenant but now we use exchange on premises

Hi everybody:
My work domain used to have a Office365 tenant but now we use exchange on premises with the same domain, so everytime i try to signup with mi work email it redirects me to a adfs page that no longer exists, nobody on it knows what happened to said tenant but it prevents me to sign up with my work email. I was wondering if there is a way to reset that and allow signups with my work domain.
Any help would be apreciated thanks