As this is an account related matter, you'll need to contact Support directly.
Replies take approximately 1 - 3 business days with Plus, Professional and Business users getting priority (longer for Basic users).
Just keep in mind that if you don't have access to the email address associated with your account, Dropbox usually cannot assist in gaining access to the account, especially if you have two-factor authentication enabled and are unable to receive the codes.
If you have a mobile device connected to the account still, then take a look here: https://www.dropboxforum.com/t5/Dropbox-accounts-billing/Can-I-reset-my-password-without-access-to-t...
Hope this helps.
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