You may want to contact a landscape contractor. They may be able to suggest some different solutions, which might include installing a drainage system, building a retaining wall, or vegetating the slope. 

Vegetation on the hillside can do a good job keeping things in place, but it may be difficult to establish if there isn't a lot of soil on the hillside. Native grasses are often a good option. Depending on the grade of the slope, terracing may also help.

Netting may work, but you can end up with animals (birds, rodents, lizards, etc. ) that get trapped under it. This would have to be anchored or pinned into place.