Subdivision Entrance

What is the name of your state? Georgia
Our subdivision is three years old. The developer built a wall and monument at the front entrance on each side of the road leading into the developement. The wall, monument, and utilities are on the property owner's lots on both sides of the entrance. The developer didn't allow for an easement on the final plat. At builder close out the developer turned over the landscape maintenance to the homeowners. We formed an Architectural Control Committee as per the developer's covenants and by majority vote of lot owners settled on a $100.00 annual fee to maintain the entrance. We ammended our covenants and recorded them with the court clerk. During the two years we maintained the entranced both front lots sold and one of the lot owners refuses to pay the fee. He has ignored numerous request for payment and only after two years stated the monument and landscaping were on his property. We had the property surveyed and it showed the wall, monument, and utilities were on his property. The landscaping in front of the wall and monument were on a 13 foot county right of way. His position is the adjacent right-of-way is the responsibility of the property owner. My question is do we as homeowners have an implied easement to maintain the entrance and is the lot owner in question bound by the ammended covenants. He refused to vote when the ballots were sumitted to the homeowners to form an ACC because he stated he didn't want to be bound by the ammended covenants. What can we do?