Fence dispute with neighbor, input based on your knowledge appreciated

[Jack B.]

I have a rental property where:

1) The neighbor has a fence that is aligned with a telephone pole which may be the property marker. Long before he or I owned our houses at this location, the neighbor/owner at the time built a fence against a hill on my property. That hill collapsed a bit and damaged his fence, pushing it over a few inches. 

2) The fence still functions as a fence and works just fine. 

3) The neighbor appears to be mentally ill, he texts me regularly demanding to know when I will do X, then Y, then Z. He demands regular updates.

4) I hired a guy to dig the hill away from his fence, but he now demands I build a retaining wall and pay to repair his fence. 

5) His driveway runs through  MY property and shares MY driveway...there is no easement on record with the county for this. Title search only found an easement for the installation of a well. That's it.

How do I get this guy off my back? Or just ignore him?