I know how you feel. I have been reporting one for 6 months now. No matter how many times I ban and mute him, he makes more alts and LL doesn't ban his IP. He has made serious threats and has caused a lot of issues with businesses. LL told me to make a police report for the threats and even after that was done still nothing.
Good Luck and I hope that you find away to get them to actually do something.