My family lives on the first floor, the old community, the fifth floor, and there is no property. What should I do if the main sewer pipe of the upstairs toilet is broken and there is no communication

My family lives on the first floor, the old community, the fifth floor, and there is no property. What should I do if the main sewer pipe of the upstairs toilet is broken and there is no communication with the upstairs owner? I want to go through court Individuals who are unable to communicate and coordinate can entrust local social neighborhood committees to intervene and coordinate. If the local neighborhood Committee can't solve it, it can only be solved through judicial channels, that is, bringing a lawsuit to the court. First of all, we should collect and implement evidence, that is, there should be pictures or videos in the leaked place, and it is best to have a written agreement or a recording coordinated with neighbors, and then bring a lawsuit to the court, and the filing fee is between 50-200 yuan.