Hi @diego.medeiros,
Welcome to the Auth0 Community!
I understand that you are no longer able to find the Payment & Billing in your tenant.
Official Solution
If you are a tenant admin you should be able to see your billing information under tenant Settings - Payment & Billing. However if your subscription is part of a Team, you will have to be a Team Owner in order to access the subscription information, which can be done by accessing your Team, then Team Settings - Payment & Billing, as mentioned in this article - Changing the Teams Payment Method for a Self-Service Subscription Team as a Team Owner.
Please let me know if this helps and if your subscription was related to a Team.
Thank you!
Best regards,
Remus