This will at first seem to be an intellectual property question, but the critical part is really a contract-law question.
I am a freelance writer. The owner of a website I have been writing for for some time has decided that he owns all rights to my work vs. the one-time rights I believe I sold him. He has nothing that indicates he has such rights; the only written contract between us was the one where we agree that I am not an employee. My work for him is therefore not work-for-hire.
Nevertheless, he has begun reprinting my work, stripping my byline from the writing. I see this as an infringement of my copyright as well as my moral rights to the work, some of which is salable to others.
When I objected, and said we had no contract that would permit him to do that, he responded by writing "Ownership of writing" in the memo line of my next two checks. It doesn't even say what writing we're discussing.
There are two checks involved. One, I'm afraid I cashed without noticing the memo line. I'm afraid to cash the other. I was going to endorse it with a "an acceptance under reservation of rights" inscription but I read that does not apply in accord and satisfaction cases. So my question is: Can I cash the check without giving up my rights? Did I give up any rights by cashing the previous check?