A licensed plumber to fix a dangerous fault at Márcia's home in Caxias do Sul

In August an inspector told me that my home has a septic backup. It's a safety risk for me and my two small children. The landlord has refused to act, and quotes of $520 are beyond us. I'm looking for a licensed plumber who may be able to donate a few hours or do the repair at cost. I can cover the parts, which I estimate at $75. The job should take about eight hours. I'll make sure someone is home and will provide refreshments. I can share the inspector's written report on request. If you're a plumber and can help, or know a program that assists with this sort of repair, I'd really appreciate it. Whatever you can give, even just sharing this page, means a lot.