Advice needed!! Client used my art to generate AI images

A while ago a twitch streamer commissioned me to draw a profile picture for his channel. He was happy with the result and after some time reached out to me again, asking for some emotes and banners, but he wasn't happy with the price i've offered him. I assumed that he would try to find a more affordable artist (though my prices were ridiculously low), but after I checked his twitch channel I saw that he uploaded AI generated art on his banner using the same art piece that he commissioned from me before as a prompt and his emotes were traced versions of my art with poorly drawn expressions on top.

I really hate that my art has been used this way and I feel that it's wrong to do so without an artist's consent. Is there anything I could do in this situation?