Clogged toilet and flooding the neighbour

Some time ago I had my toilet clogged. I have my flush and pipes behind the wall. The pipes are build in the way that one goes in another. The pipes was clogged below the merging point. When the water didn't want to go, it found its way through the merging point. And now I have a problem. Because of that we flooded our neighbour below. Our flat owner says it's our fault, because we clogged the toilet and we say that it's the owner's fault because of the faulty pipes. What do you think? I made some drawings along with picture and a short video.
Drawing: http://i.imgur.com/MkcEcZl.png
Picture: http://i.imgur.com/b5kqqTb.jpg
Video: [ame]https://www.youtube.com/watch?v=xuVSeEG5I1s[/ame]

What do you think? Whose fault is it? Mine for clogging the toilet, or owner's for having bad pipes?

I would say It's the owners responsibility. The waste line needs to be repaired, it should not leak even with a plugged drain.

looks to me the reason you are having a clog is that ..what ever you call it, illegal flex connection,,those ribs, will cause a clog because the paper will get caught on them. your toilet is not hooked up per upc code.
i do not know where you are, so cant say

that joint should not leak, that is a health violation.

tell your land lord to eat.... and bark at the moon!!!

What country are you in.

Allright everyone. We had a plumber here and he said that it was badly done pipes that caused the leakage. So I was right. Thank you all for your replies, you helped a lot .