Welcome to the Auth0 Community!
It seems that the tenant you deleted was the only tenant on your account. When you do this, it deletes your account. Hence why you are not able to create any new tenants. Generally, you will want to create your other tenant before deleting the one you intend to prevent deleting your account on accident.
(Reference: How can I delete my Auth0 / Auth0 Community Forum account?)
At this stage, we would need to internally remove your account to allow you to recreate the account. Alternatively, you can create a new account using another email and password combination, or consider using a Social Identity Provider to log in, such as Google.
Please let me know what you would prefer to do.
Thanks,
Rueben