Georgia - can a neighbor just tear down my fence after obtaining a survey showing property line runs through my side-yard?

Location: Atlanta (Fulton county)

I’m looking for guidance on what type of attorney I need and/or whether I have any legal options beyond simply accepting the “new” surveyed property line.

I own a home with a narrow side yard walkway (4 feet wide in total) between my house and my neighbor’s fence. The fence line has existed for many years (10+) and was treated as the agreed upon practical boundary between my property and his with no issues.

During construction of my house, a retaining wall needed to be built, but the neighbor came out complaining that the wall could not be placed all the way up against his fence, and that the official property line was 16 inches off the fence line (this man came out with a tape measurer and told us exactly where to put the wall). I didn’t care to argue with him, so I just said “sure, whatever. Put the wall wherever he says” and we did, and that was that.

In addition to the retaining wall, drainage improvements (French drain housed inside the retaining wall) and other site decisions were made based on that understanding.

4 years pass without incident. Then recently, my neighbor obtained a new survey. This new survey says the true property line ISNT the 16 inches he originally thought, it’s actually smack dab in the middle of the walkway created by the retaining wall.

I reviewed both his 2025 survey and dug up my original 2018 survey, and they appear to agree that the legal property line actually runs through the walkway, approximately 1.5 feet away from my house (the walkway is approx 3 feet wide, and then there’s the 16 inches of unusable space - about 4ft total), although it’s not like we have it nailed down to the inch on where it actually is.

After obtaining this survey, my neighbor then decided he wants his 16 inches back, so he came over and removed a section of fencing that had been in place for years (securing access to the side yard) with a sledgehammer/axe and has begun accessing and modifying the narrow 16 inches strip between the surveyed line and his existing fence. He’s claiming ownership of that 16 inch area based on the survey, and over the last few days comes and goes as he pleases basically having uninhibited access to my side yard and the connecting backyard. If I try to put up any fencing, he just pushes them to the side saying “you can’t obstruct me from my property” (the 16 inches). It sounds like, for now, he’s fixated on these 16 inches, but I have a feeling that’s only the beginning, and he’ll be coming for another 16inches next (since he believes the TRUE property line lies right down the walkway)

My questions are:

1. What type of attorney should I be consulting (real estate attorney, property litigation attorney, etc.)?

2. Even if the surveys are correct, do long-standing fence locations, retaining walls, drainage infrastructure, and years of reliance on a different practical boundary have any legal significance?

3.If a neighbor believes a survey establishes ownership, are there situations where they are still expected to obtain a court order or other legal remedy before removing existing structures?

I’m not asking anyone to determine ownership of the land. I’m trying to understand what legal issues may still exist assuming the surveys are accurate.