Hello, I would do a Factory Reset if you haven't done so already:
Open Settings, and then select General.
Select Reset, enter your PIN (0000 is the default) and then select Reset.
To complete the reset, select OK. Your TV will restart automatically.
If these steps don't match your TV, navigate to Settings, select Support, and then select Self Diagnosis. Reset will be located in that menu. You can also check the user manual for exact instructions for your TV model.
See link below for more information: