I have put it under harassment. Then make sure to copy and paste the whisper into the body of the report. I've gotten responses to both reports I've sent - they were the generic Thank you for taking the time to report phishing attempts reply and that since they get a huge number of these reports they don't have a GM come for a personal chat with you about it. I don't think the support team is bothered about which you choose to report phishing attempts under.