After that much time, your account was likely deleted. Dropbox will purge unused accounts after a period of time (usually one year). If that's the case, then your files will be unrecoverable. If that's not the case and your files were simply deleted at some point while you were using the account, then they can only be receovered if deleted within the last 30 days. Either way, only Support will be able to give you information regarding yoru account, so you'll need to open a ticket.
Open your ticket here: https://dropbox.com/support
Track your ticket here: https://dropbox.zendesk.com
Replies take approximately 1 - 3 business days with Plus, Professional and Business users getting priority (longer for Basic users).
