We bought a house about 2 years ago that was vacant for about a year. We completely gutted and remodeled the home. About 4 months ago we finally got the toilet working. This was the only running water source in the house for the last 4 months, no bath, kitchen, or bath sink. We noticed a leak in the basement sewer pipe and in the midst of fixing it, we figured we would have rotor rooter come in and flush out the lines. They claim that there is bloackage about 11 ft into the pipe and the think it's dirt. The pipe is cast iron that runs under a cement floor crawl space. My questions are -

1. Because the house sat so long without running water, could it be old feces hardened causing some blackage?
2. On that same note, we only ran a toilet for 4 months and nothing else. Could this pose a problem not washing the solids down properly?
3. Does solid waste actually sit in the pipes until more water washes them down? The pipe is approx 26ft of run before connecting to the town sewer line.

Thanks for any help given.