My house on a hill has been gradually moving down the slope. My windows have an almost 1 inch gap on the down-hill side. The plaster is cracking throughout the two stories and the basement slab has a two-inch drop. Recently my neighbors cleared the ivy on the fence that seperates our two properties. This revealed the fact that when the previous owner excavated the slope to build a new garage he failed to provide any retaining wall at our common property line. This is obviously the cause for my house to be leaning. I should think that this is an obligation that should be my neighbors', not mine (I did'nt live here when the garage was built). Her response was that it is my responsibility to build the retaining wall on her side........I can't talk to her. Advise? This is a serious problem as I'm afraid my whole house could fall or collapse due to the fact that the foundation does not bear on firm soil.