The first priority is safety — keep people and vehicles away from the slope and wall zone immediately. Then start documentation before anything is moved or cleaned up: take wide photos from multiple angles, close-up photos of all damage, and a continuous video walk-through of the entire failure. Note the date, time, and what you observed happening. Call your insurance company to open the claim the same day, and contact an engineer or experienced retaining wall contractor to assess the site within 24–48 hours while conditions are still unchanged.
