Hi @old account empty, thanks for joining the Community!
Files on a Dropbox account aren't automatically deleted after sometime. They can only be deleted by users, so Dropbox doesn't affect your files at all.
Are you able to see the deletions from the events page? If the missing files were deleted within the last 30 days you can try to recover them from the deleted files page online.
If you need any further assistance, please let me know!