Hey @A_E, thanks for joining our Community.
When you downgrade your account, your Vault becomes just a regular folder in your account.
So, if you only want to access the files in your Vault, they should already be in your account.
If you want to have access to the feature again, you'll need to re-upgrade your account to a Dropbox Plus, Professional, or Family plan.
Let me know if you have any questions!