Hi Burak,
probably only the Split Points are set "wrong".
Please press [Direct Access] - - - > [Sync Start] to bring up the Split Point setting display.
Then set both Style and Left Split Points to the SAME note (default value is F#2 for each).
Then set the Right3 Split Point ONE semitone HIGHER than the Left Split Point (by default to G2).
Press [Exit] button to save the settings to the System Setup.
Now you can play Right 1, 2 and 3 in all combinations.
To recall your Split Point settings later, you have to memorize it to a Registration. To get ALL Split Points stored in a Registration, the boxes Style and Voice must be checked.
To prevent Split Points from unexpected changes (by Registrations or MIDI files) you can use "Parameter Lock" function. Please refer T4 Reference Manual, section "Utility" for more information.
Hope this helps!
Best regards,
Chris