I think the best way to address the unauthorised use or manipulation of creative work is to ensure it is clear what can and can’t be done with the work you sell, license or publish.
It’s crucial to look out for misuse of your work and tackle it promptly. Remember that the law is on your side. Make sure the infringer knows you are serious, but give them a chance to put it right. Also, consider how your actions will be seen by existing and future customers or clients.