Damaged sewage

Hellopeter. I'm seeking for some legal advice. It happened that I fell into a sewage which falls under the municipality. The sewage is next to a local restaurant where I decided to grab some take-aways. The sewage was covered with a little piece of rust shack and I sustained lot of injuries where I wasn't able to walk for that week and I have a medical certificate to prove that I got hurt on the incident. There are some kids and old people who are passing by that sewage and I feel bad because it won't definitely happen to me only but some of innocent people who are bypassing that section. I went to local municipality to consult with them and they told me that they will get back to me, till this day I've been waiting for them to call me but they are not keeping up to their promise. I would like for you to help as it is getting out of hand because the municipality is not sticking to their own words and even now they have not able to make some changes towards the sewage as it is still damaged.