Your landlord should deal with this, but your lines should be snaked and worst case a camera run down there to see where the plug is, (expensive though)
The cleanout drain in the front yard is leaking waste water everywhere . The cap was busted off and its open. Every time water is turned on , it comes out of the cleanout drain. The bathtub was backing up , but is now flowing fine, however all of a sudden when I flush the toilet, it backs up into the downstairs sink. I called the landlord, his team are looking it over as well as the other apartments but seem confused . Is there a clog in the lines in my house or is out in the yard or near the main sewer line ?