If you have the wash, rinse and service light lit up then this is error code F12 which is a heating error code.
What you need to do is remove the back cover and there you will see the heater in the back of the drum at the bottom.
From there check the wires are still attached on there.
If the wires are fine then you need to test the heater with a multi meter. It should read about 28 Ohms. If faulty then you need to replace the heater from there and that should clear the fault and get the washer working again.
So the error code you have is a heating error code so check the heater and wiring and see what you find. As if the heater and wiring is fine then im afraid its going to be a faulty circuit board in there.