how can i fix my simpson eziset 550?

Hi
My washing machine just keeps on filling with water, overflowed once and now i cannot get it to stop filling up.
I have followed the advice on this website as a lady had the same problem and took it upon myself to change the level sensor and check the vacuum pipe.
With new sensor and zero holes in the pipe i am still having this issue.
We have however had one successful wash cycle since the change over, but have attempted over 12.
HELP ME PLEASE!!!!!!!!!