How to fix my Zanussi Aquacycle xc6 1400 washing machine?

My Zanussi Aquacycle washing machine only works for so long it washes drains, rinses, then only partly drains and says end instead of completeing the program when stops you then have to press the button again and it will drain then click door lock can be open light off. then you have to manually turn the dial to spin to get it it go again, but it does not spin all the water out as it should , and you get wet feet if you take the washing out thinking it is finished?? Help I think it might have a blockage but wouldn't know where to start.