@julianperretta managed to get his account back, but last I checked he seemed to have stopped retweeting without attribution.
Twitter is really slow on addressing this issue, even though it’s in violation of their TOS.
The best hope of getting someone to stop:
Request they remove specific tweets
If they don’t (after at least 24 hours), report them.
And keep reporting them.
This is definitely a “squeaky wheel” issue. Twitter seems to only address it when it generates a significant amount of noise.