My sympathy. It is like a splash of cold muck when people aim charges against you like that.

I know some artists who brainstormed a great idea, then were much surprised when one individual of the group claimed the creation! He publicly accused them all of copyright infringement: a stain that took a while to fade. 
The incident left a lot anger and sense of betrayal. So, I can guess what you're feeling.  What helped my friends was to continue their art with their own special inspiration, sticking to the facts about the incident and refusing to let it grow beyond his arrogance.
Good luck