The gallery has a huge problem with plagiarism right now unfortunately. I realize it's not a valid reason to report but when someone create 10-15 accounts to do this it's something else. When someone create an account just to use that account alone to reupload the creations to one creator it has hit another level. This is harassment and needs to be looked into by EA and hopefully find a permanent solution to deal with this kind of behavior in the future.
It's understandable you are upset Buxytone, but if you block them they will not be able to follow you and not be able to write anything on your creations. It's okay to speak up if you see this kind of behavior but maybe comments on the reuploaded creation isn't the best solution because you never know what kind of respons you get. Follow Lynariela's advice and go to the original creator and he/she will deal with it if they want to.
I will then ask anyone that see what I described on the top of this message to write a report to EA because this is not only reuploading it's harassment. I have sent reports to EA about this problem and will continue to do so.