drain
It's a good thing you are not a lawyer.
1. The sewer is in an easement, which is public property as far as access is concerned.
2. The utility normally only maintains the main central sewer, and is some cases, such as around here, the actual connection to the main is your responsibility even if it has to be replaced due to breakage.
3. If the sewer is made of one of the stoppage prone materials, it should all be replaced, even if the current problem is at just one point.
4. If the neighbor showed you a mass of roots, then that implies that the sewer is made of a poor material or is damaged.
5. All the utility will do, if they were called, would be to insure that there is plumbing permit, possibly an encroachment permit to work in the easement, and the necessary inspections. All of these will do nothing except add to the cost of the job, assuming the plumber is doing the work properly.
6. If the plumber has a bad reputation, why is the neighbor having him do the work?