- Designer has rights and his requests should be honored
- The Company has all the right and their designer is created the design
- Need more info
Lawyer up and hope that your NDA was properly written.
However, keep in mind that if they scrap the project or remove aspects which you believe you influenced, you are SOL.
Are you a contractor of some kind? Or freelance?
As Cyberdemon says, get a lawyer. In fact you should have done so already.
Reading through your story, it seems you’ve done a lot of things right. You’ve got an NDA which proves you met the company before they hired the interaction designer who they’re now saying had the idea for the design. If you have proof of dates of when you developed the work, that’s the start of a good case. You’ve also behaved calmly and professionally. You should probably have tried to get some kind of contract in place before meeting them a second time, but I’m guessing it didn’t feel definite enough at the time. But you made a big mistake when you listed what you wanted to release the work. This is the point where you should have sought legal advice.
By asking what your demands were, the CEO made an admission of your ownership of the design. What you did then was list (honestly) what you wanted - what you should have done was make a list with extra demands, as the basis for negotiation. As it is, you can’t get everything you want unless you refuse to negotiate, which makes you look unreasonable. Also, your monthly fee is irrelevant. Since you weren’t hired as a consultant you have the right to charge the maximum that they will pay. The price of a Jackson Pollack isn’t based on how long it took him to paint it.
If they refuse to play ball, there might be a few things you can do. One is to start publicising the work (yours, not anything this company have added) right away. Get it out there in as many places and media as possible. Then when the company release their version, tell people it was based on yours. Don’t say they copied or ripped you off, make it sound like you worked with them (which is sort of true). If you go about things in the right way it could make a good piece in a professional portfolio. Alternatively, publicise your work but very quietly. Then when the company release their version send a cease and desist based on copyright infringement (you definitely need a lawyer for this). If the work forms part of a PR campaign, there’s a good chance they’ll try to negotiate rather than see their shiny new campaign flop. There might be a ‘middle way’ strategy between these also, but only you can decide how hard to play things.
One other thing, forget about a good relationship with this company. What you want is a business relationship. By staying on ‘friendly’ terms you allow them to manipulate you; chances are they’ll say they can’t afford what you’re asking, or that you’re being unreasonable, or even that you’re blackmailing them. Working through a lawyer insulates you from all this.
+1 on a lawyer. This is where designers try to step out of the zone of our abilities. Do the smart thing, hire a professional!