I had a similar problem some months ago with a prominent blogging platform and I ended up sending an email to the tech contact in their WHOIS. I got a response

I had a similar problem some months ago with a prominent blogging platform and I ended up sending an email to the tech contact in their WHOIS. I got a response in less than one minute from a guy who wasn't working directly for the company, but for their hosting provider. He got the security issue fixed in something like three days. Try WHOIS, you'll hopefully reach someone tech-savy enough to discuss with.