Are you running into synchronization problems in the app, because refreshing doesn't seem to work? The session may have expired. Normally SURFdrive will have to come up with a refresh automatically, but you can also force this manually.
To manually force a refresh:
Click on your profile at the top right of the screen. In the menu that appears you will see three options: Two arrows in a circle, a key and a trash can.
Click the arrows to force the app to sync.