I am going to try and keep it short but I don't know how much background is needed.
I worked for someone. I created a product for that someone. We had a falling out and I no longer create product for this person.
I now create product on my own. Product that is similar (educational materials) but by no means identical. However, it is similar in that most products within this specific genre have one or more of the same items. Again not identical but similar. Example - word scramble. They pretty much look the same regardless of whose book they are in but they format, font, words etc will vary.
I created my own, different (from a blank slate) product. It is in direct competition (there is no non-compete agreement). However, there is only ONE (I repeat ONE) clipart image that is the same. This image was purchased by ME from a totally separate vendor than the other person used. That alone would be the only identical item.
This other person is not emailing me to cease and desist, requiring me to take down my product and is complaining to vendors that my product violated copyright.
Based off the info I have given here (which is the utter truth!) would I be violating any copyright? Please feel free to ask any questions. My gut feeling is that this other person is just trying to keep me from making a product that is in direct competition but I don't have proof of that.
One other thing. How does she prove copyright infringement? I have not sold any product yet and the sample is only 6-7 pages. If she obtained a full copy wouldn't it be a pirated copy? If a vendor gave her a copy can they be help culpable?