What legal recourse do I have if my sewer has been backing up?

I live in an older double home and there are three houses connected to one sewer line. My neighbor said that he was having the same problem but his plumber fixed it. I called my plumber who discovered that my neighbor's plumber broke the pipe/trap that keeps dangerous fumes underground. My plumber called the health officer to see that I have raw sewage in my basement. The officer said that since all three houses are connected-all three must pay for the repair. Why should all three of us pay if my neighbor's plumber broke the pipe? Meanwhile it's been over a month and the health officer said that he's still "working on the problem". My mom and I are experiencing health problems-sore throats, difficulty breathing, etc. from these noxious fumes. The officer said that my neighbor is going to get a plumber friend of his to do the repairs and he will split the bill in three. I don't trust my neighbor anymore or his choice in plumbers. What can we do legally-if anything? Please let me know. Thank you so much!