If your sewer is clogged the first step would be to have it snaked. While the drain is being snaked, the plumber should be able to determine if further actions should be taken. If roots are pulled out of the drain, depending on the diameter or thickness of the roots, you may be able to treat the drain with a product called “RootX.” This is about the best root treatment on the market. Once you have had it applied, if the contractor files the proper paperwork, RootX will send you a reminder post card each year reminding you that it is time to re-treat. If you treat yearly, RootX will guarantee your drain to be free of roots for the life of the sewer line. If the plumber find thicker heavier roots, it is probably a good idea to consider replacing the sewer line. If the plumber feels there may be a mechanical problem with the drain, I would recommend that you ask to have the drain inspected with a sewer camera. This is a high definition camera that would be fed through the drain and can be used to find breaks, sags, man made obstructions (toys, balls etc…) and then it can be determined how to remove blockages or determine where or how much of your sewer will need to be replaced.
First step you should take is to open the drain and allow the stoppage to flow to prevent any back flow of dirty water into your home and cause damage. Once that is taken care of, I recommend that you put a sewer camera in to provide a view of the condition of the pipes. If a collapsed pipe is present, repair. If root intrusion is present, replace pipes. Roots are persistent and will return. If sludge or build up is present, try to high pressure jet the line (depends on age and condition of pipes) to fully open pipes.