@Nuray wrote:
i couldn't reach the files in my drobbox account that I started using in 2016 when I logged in and looked at them today.If I upgrade my account, will my data from my old account be returned ?
You can look at the Events page for the account to see if there's any recent activity. If so you might be able to recover files if they were deleted within the last 30 days. Upgrading now will not change anything.
If your account had been idle for more then a year, then it would have been deleted due to inactivity, and you're likely signed in to a new, empty account. Unfortunately, once and account has been deleted, neither the account nor the files that it contained can be recovered.