structural damage acuring from retaining wall

My house sits on a hill where the houses around are very close together. My neighbors house sits 50 ft futher back than all the other houses on the street. My driveway is very tight my house is on one side an my neighbors yard is around 3ft taller than my drive held up by a retaining wall on the other side. you can barely squeeze a car between the house and the wall.the wall is made up of 6by6 wood beams stacked up and anchored underground in his yard.over the last 15 years, since i moved in the wall has been shifting twards my my house making it a tighter fit for a car but also pushing against the cement driveway causing basement blocks loose and pushing inward. the neighbor claims the walls not his responsibility. if its my problem i would take the wall down causing his yard to collapse onto my drive and use his soil for fill dirt. where do i get help with this? do i need a lawer? do i get property line suveyed? what is my first step in dealing with this problem? any and all help appreciated.

Yes get is surveyed and then you can take any action within your line that you wish (within reason)--and you can force them to take action on any problems that cause damage on your side but come from the other person's side,