My Hotpoint Aquarius washing machine WF350 keeps flashing Prewash?

Hi my washing machine keeps flashing prewash when i click start it starts as if water is going in but its not going in the main part to where the powder is then stops and keeps flashing prewash,checked brushes which seem to be still ok,the only cycle that the drum seems to move is on a rinse and spin but the prewash light is still flashing,would you advise me please thanks