Out of curiosity, where have these details been posted besides this forum? I'm not trying to nit-pick, I'm honestly asking because I haven't seen any of these details released to the public yet. If there is an official method your organization is using to respond to these allegations please pass along those notes so we know where to go and get your side of the story. If there is no such platform yet, then maybe you should reconsider wagging your finger at the community for not understanding your point of view. At the moment this is a matter of perception that is being weighed in the court of public opinion, and because of the (apparently) blatant facts that have been released in the last few days it can't be much of a surprise that the current opinion of the community is running against you. If the Infosec Institute means to manage the message on this issue, then they should get a coherent, complete, and reasonable explanation out in a hurry. You asked for recommendations so, off the top of my head:
-Peter has gone out of his way to document his communications with you, grievances, and legal proof of his allegations. He then made these publicly available. You could do the same. Currently it seems like your organization went incommunicado on the issue, and that vacuum isn't helping perceptions. If you've actively been working through this then show it.
-The "it was a contractor's fault" response is going to be a rough road if you decide to take it. You might find some legal coverage by playing that card depending on your contracting and the skill of your lawyers, but within the security community I'd expect more blowback than forgiveness. You don't just trip and accidentally copy an entire (massive) work from a well known individual, do a crtl-f find/replace for names, and build an entire course around the material without someone within your organization noticing. That just doesn't pass the scratch and sniff test. For many of this it sounds a lot like one Mr. Gregory Evans. (http://www.amazon.com/How-Become-Worlds ... 0982609108
) Please explain how this made it through all of the expected reviews/planning/etc that would go with building a course without someone in your company realizing what was going on. Otherwise, are you stating that you simply bought, without any review, the product of a contractor and immediately started selling/teaching the material? Do you do this with all of your materials? Have you initiated a review of all of your other course materials to make sure this isn't systemic?
-A quick check of your website shows that the CEPT certification course is still being offered. It also shows that the course includes "9 domains". Are these the same 9 domains that were in the course previously? Meaning, are you still offering the same course with the same material that is the source of these allegations? Your posting seems to imply a significant amount of due diligence was performed after you were informed of the plagiarism... did that not include removing the course from your site? Are you still making money from Peter's material in any way? If not, then explicitly state the current status of the course and material.
Again, this is just a response to your request for suggestions. If you've already answered these points in some other format then please let us know where. A quick review of your website doesn't seem to show anything.