Found a sinkhole while flipping a home in Atlanta

[Jason Nguyen]

While renovating a home in Atlanta (East Point City to be exact), we found two sinkholes that are causing by the stormwater drainage pipe that is leaking under the neighbor's driveway. It has been releasing rain water from the entire neighborhood and causing two massive sinkholes that are spreading under his driveway, to his yard, and all the way to my property and has damaged the foundation of my house. The neighbor doesn't seem to care if his home is at risk of collapsing or my house will be collapsing soon. I sent this over to the city, and they said that the pipe is within private property, and they are not responsible for it. The neighbor has refused to fix it, and my house is at risk of collapsing within months. What should I do now? I cannot send the crew in to fix the pipe since it's under his driveway. Any help will be very appreciated.