We have a kenwood kdw12st3a

Question

we have a kenwood kdw12st3a dishwasher - ever since we have had it, it has been nothing but trouble. It constantly flashes e4 so we have tipped it and drained the water out of the bottom (as advised) and it works for a couple of days then happens again. Now it refuses to work at all - cant set a programme - nothing at all - please help!