What should you do when your business has been hacked and is being defamed online?

A few weeks ago, someone got access to our customer data, and posted a video on YouTube claiming to be hackers and published defamatory content about us online - with details of our customers. The attack has since spread to 8 videos on YouTube, FB, Vimeo and DailyMotion - along with several comments online. We've had a hard time finding the person, and our lawyers are asking for a large sum in order to obtain a UK court order for these sites to disclose the person. I'm not sure that would work as they've used anonymous names and email addresses. We've also had limited success with those sites. They are agreeing to block the content in the UK only, but not globally. What should we do in such a situation? I fear for the longevity of our…