A licensed HVAC technician to fix a dangerous fault at Aisha's home in Alcalá de Henares

In February 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 $1,050 are beyond us. I'm looking for a licensed HVAC technician who may be able to donate a few hours or do the repair at cost. I can cover the parts, which I estimate at $130. The job should take about six 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 HVAC technician and can help, or know a program that assists with this sort of repair, I'd really appreciate it. Even a small gift gets used right away and I'll thank you myself.