Hey there @IreneRx, thanks for reaching out to us here!
If you've unlinked the device from your account, then your account will no longer be signed into the mobile app on that device. The files within your account won't be accessible anymore through the mobile app.
Just as an additional step, if you were signed into your account through the web browser on your device, I can also suggest removing old web sessions from your Security page too.
You could even change your Dropbox password as another security step in the case that your password was saved through the web browser on your phone.
I hope this helps, let me know if you have any questions!