Phone is reporting using more space than the total available storage
I would first try booting into stock recovery (look up how to do it because its device specific) and then using the volume buttons navigate the selection to wipe cache. Not wipe data! Then click the power button and wait for a while while it does its thing.

If that doesn't work go into app manager in settings and click on Google play and hit wipe data (do the same with Google play services). You will have to sign in again but it should fix the problem if it's a problem with the play store.

If that doesn't fix it, try clearing the data of the settings app (I'm pretty sure you can do this in the app manager in settings (it will wipe your settings)).

If nothing else works then backup your data using Helium Backup (if you want to keep your app data), Samsung Kies (you would probably have to use an older version), or just having all your stuff in the cloud) pictures, some games etc.), then go to settings and find where it says backup and reset (most likely the accounts tab) and click factory reset. Make sure if you used helium backup that you backed up backup to the cloud or an external SD card if you have one. Then follow the instructions and presto, it should be back to factory settings when it's done. If not you might want to look into flashing stock firmware with Odin or Kies (only as a last resort and with extreme caution).