Tank indicator V40 1.8

Hello, I’ve been having a problem with my tank indicator for quite some time now, which quittered your service after I wanted to go home to work. The tank indicator continued to sink into the reserve area until at some point the reserve lamp turned on, a full tank had no purpose, remained constant in the reserve area with reserve light over several days. Meanwhile, however, when the car starts to show me a minimum tank content, this during the drive into the reserve area sinks to rise to maximum during the ride, which is not true, since only half the tank content is still available. Look forward to your answers.