Whats wrong with ,my beko DE3430FS wont drain and water cold?

hi my beko DE3430FS dishwasher fills with water and makes a noise as its washing goes through cycle but doesnt drain and when you open the it water thats still in it is cold have already checked pump impellor that was fine nothing jammed if heater or thermostat would it be expensive to fix and do you think it worth getting fixed can anyone help