how can I fix my hotpoint wmt01?

Some cycles work somedays then dont work other days. It sometimes doesnt rinse after a cycle and a couple of times it hasnt filled properly as i took clothes out and some were wet, some were dry. When a cycle actually starts, after about half an hour of fiddling with it to get it to start, the cycle only works for around 20 mins then stops but nothing is clean. The only cycle that seems to work is the boil wash. on this cycle it even does a fast spin. I dont understand how the wash and spin can work on one cycle but not the others.