sewer belly

Getting my basement finished and had my sewer line cameraed to get ahead of any issues. It's 4 inch PVC under slab installed in 2020 by a company I no longer have confidence in. The camera identified a belly in a section of the pipe that was holding water and submerged the camera, but minimal...

New home on slab, moved in end 9/2021. Downstairs full bath and powder room, upstairs full bath. End 4/2022, downstairs toilet clogged. Husband plunged, then other downstairs toilet clogged, then sewage backed up into downstairs shower. For most of the 7 months before blockage, just one person...