IANAL;
Regardless on who is at fault. Intellectual theft is stealing or using without permission someone else's intellectual property.
Intellectual property is any creative or commercial innovation, any new method that has economic value, or any distinctive mark which might include a name, symbol, or logo that's used in commercial practices. This type of property includes ideas and property protected by trade secret laws, trademarks, patents, or copyrights. Client lists, mechanical inventions, poems, logos, and other items can be covered under intellectual property.
In order to qualify as theft, intellectual property typically has to be used without the consent of the owner. If your intellectual property is used without your permission or is stolen, there are a few paths that you can go down.
First is to ask the person who is using your intellectual property without permission to stop using your intellectual property. It's possible that the person committed intellectual theft without intending to do so. If this is the case, the person will likely stop using your intellectual property or agree to pay you for your intellectual property. If asking the person who committed intellectual theft to stop doesn't work, you may have to resort to legal action.
I would strongly advise to contact a lawyer in the matter.
Good point! lol