It has happened to me on several occasions and is so frustrating.
Exactly a year ago Getty Images contacted me to advise they had instructed their lawyers in China to take action against a company that was profiting from selling thousands of copies of stolen images. One of my images was involved and Getty advised they would seek my assistance and my immediate thought was that I don’t want to go there to give evidence given that the virus had escalated. Thankfully about ten days later I got a document to sign just to confirm that I was the owner of that image.
I have come upon 4 of my images that have been used without my permission and placed on their websites. One person was so bold as to remove my watermark and add theirs. I contacted all 4 of them giving them 24 hours to remove the image or face legal action. 3 took them down immediately but the one who removed my watermark insisted that it was theirs. My across the street neighbor was (he has since passed away) a corporate attorney and he drafted a letter to the guy for me on his letterhead. It was gone by the next day.