If Dixon is as big a mess as indicated downthread, you may be on your own here. If you wanted to get it done instead havin git collapse while you're sending messages in a bottle, you could hire a contractor yourself and withhold the cost from the rent. As long as it's meticulously documented, including the log of attempted contacts, you should be fine.

Or you could withhold rent and put it in an escrow account. That will get their attention. I think that the Housing Court even manages escrows, but I don't really know.