[Auftot]

You have 3 options (that I think of):

1. Send corrupted files, this may take a few extra emails and persuasion but is definitely the easiest. You can corrupt files here: https://corrupt-a-file.net
   
2. You can find some photos or buy some photos of a g933 and edit them to your serial number yourself. If you do this make sure to change/edit the metadata so that Logitech doesn't know it's edited. This method only costs a small amount of money as you only pay for the photos and not the editing, unless you can find your own photos. You can learn how to delete metadata from here: https://www.google.co.uk/amp/s/www.windo...s-10%3famp(this is for Windows 10 if you use a different os just Google around for how to edit photo metadata)
   
3. This method is more expensive than the other two but requires no work from you and will have a higher success rate. Basically you buy photos then pay someone to edit the s/n on. Double check the metadata is right and doesn't say that the photo was edited in Photoshop.