However, I will recommend you (albeit reluctantly) to factory reset your TV.
Another way out of this situation may be to disconnect the TV from the power, and it is done in the following order:
-turn off the TV from the remote control.
-disconnect it from the power supply
- disconnect all other devices from the TV
-Leave him like this for a few minutes
-connect the TV to electricity
-plug all other devices
-turn on the TV with the remote control
You should also do something like this with the decoder, i.e. disconnecting from the power supply or restoring the factory settings.
The downside to restoring your hardware to the factory state is that you will lose your saved settings.
If these options fail - the TV submits to the service.
PS write what exactly Polsat decoder you have and what TV model you have.