I had a similar experience and had to shut down my website, and rebuild. I had no way of finding out who the culprits were. I am no webmaster, so consulted with a friend and this was the only solution.
This also happened about the same time in July.
I have had a lot of financial problems and as such my website is to be completed to some degree this weekend. It has cost me a lot of heartache and pain to say the least.
My question is, how do you stop this from happening again?.
You mention sending C+D to the host, can you explain a bit further?
goodluck222( not much luck there)