jbirds99 - sorry to hear of your dilemma! i would want to know from the builder where my property washed off to and will he be putting it back - stabilized!
this website may give you some info and enlightenment
How to Stop a Washout on a Hillside Landscape | eHow
and before you do anything else - i would suggest that you take photos - from a variety of angles. you might need documentation at some point.
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Not sure if I have free time...or if I just forgot everything I was supposed to do!