Plumbing and Black Mold?

I have been living in a house that I rent for about 3 months. We were told by the landlord that the house has been vacant for a year. When we moved in we had to lay our own carpet. Money was taken off of the rent so that was fine with us. Then little by little everything that needed done he asked us to do, with no rent taken off. It was small things like putting doors on and light-switch plates up. Now, its a bigger issue. About 3 weeks ago our plumbing went hay wire. Water from the tub, toilet, and sink are going into my basement flooding it and ruining a lot of my things. This was late at night and the person I rent off of has an office. So I called directly the next morning. I left a message. I called later in the day, left a message. The next day I called and left a message. The day after, they finally called me back in the evening. They came the next day and did some things and didn't fix it. The next day, nothing. The day after they came back. They didn't fix it. They said they'd be in contact. That was a week ago. Still nothing, I have called and nothing. My house smells like raw sewage. Also we were told there was black mold in the house and that's the reason the person before left and its been vacant for a year. What should I do about plumbing and should I be concerned for black mold??