I conceived and co-developed (including the program itself and training protocols for participants)/piloted the program locally/managed three national pilots, and assessed the effectiveness of the program including formulating the written proposal to public and private funding agencies that laid out the essential elements of the program and writing reports. Years later, one of my co-developers claims sole responsibility on line (at a University web site) and at a non-profit spinoff's web site for this and another program I conceived and co-developed and has wiped me from the record. He does not credit our co-developers, upon whose ground breaking research much of this work rests. If one (say a member of a selection committee) were to take a tour of the Internet using the usual search engines, it would appear that my CV and resume are one big lie after another. I inquired of Legal at the University where I did the work, and they said they have no control over what a department head puts on line and that it is if anything a compliance issue. What does this mean? And also, do I have a moral right and what kind of recourse might there be? Basically 15 years of my life is now invisible.
First off, you should decide what exactly you feel is wrong, and how you want it to be. You were involved in the early stages of this program, but others took the helm later. They continued to put work into the program, and they deserve credit. Arguably visitors to the program website want to know about who's managing it now, not its history. Do you want to be cited as a co-creator or founder or first director? Do you want a section dedicated to "early work on this project" where you play a greater role? Is this really that important, since in academia publications are the currency of value, not websites.
Second, once you've decided what your objection is, you should take this objection to the co-developer in question. Perhaps this is just an honest misunderstanding and he/she will rectify amicably.
Third, if you get no resolution, then you need to decide whether you want to pursue this further. Read your co-developer's response carefully and objectively. Do you think they have a reasonable case? If so, you are unlikely to achieve anything positive by pursuing this (in fact, going to the legal department may have been a mistake). You will (further) sour your relationship with the co-developer, and have the potential for getting a bad reputation.
Lastly, if you are absolutely certain that your co-developer's position has no merit, and you really want to pursue this further, you can try to apply pressure to your co-developer. The legal department is the wrong avenue, as their job is to protect the university, not police it. Try the dean, or otherwise the supervisor, of the co-developer. If you can prove that the situation has cost you financially (farfetched) you might consider a lawsuit.
I suggest a different strategy than that proposed by vadim123. Don't engage with your co-developer or his institution at all.
Instead, write a blog post (or posts) or a white paper telling your version of history. If it is a white paper, post it on your web site. Better still, arrange an interview with a web publication, with links to your white paper. You are done.
In any job application and CV, you should link to your blog posts and white papers, or related articles. If any search committee spends any time on this, and also sees the web pages of your co-developers, they would probably ask you to explain the difference in stories. You will happily explain the differences, with no need to explain why the co-developers wrote what they wrote.
The advantage of this approach is that you don't need to persuade your co-developers or their employers of anything. No legal process at all. You only have to invest up-front time to write your story in a compelling form (hopefully, backed with substantiating evidence), and then deal with questions as they arise in the interview process.