I'm in St. Louis County and was having issues with my sewer line backing up. My front yard was also sinking in one spot. After having it snaked several times over the years, I finally broke down and got someone out to run a camera down it. The pipe had separated at a joint under my front yard. I was afraid of this which is why I had put it off for so many years.
So the guy that did the camera tells me he will make a video and send to the county and they will be out to fix it soon. Turns out part of the fees you pay for sewer covers repairing the line between where it enters your house all the way out to the street.
The county had a contractor come out and dig up the line, replace with PVC, add a clean out, and backfill. Took them 4-6 hours, seems like it was about a week and a half from when I had the camera done.
All it cost me was the camera guys fee, seems like $200, can't remember for sure.
Wish I had known that 10 years ago.
Don't know where in MO you are, but you might want to give the sewer company a call.