BadgIRT (Incident Response Team) is a group of volunteers that is available to respond to threats involving information technology resources, including denial of service attacks, inappropriate use, and harassment. If you fear for your physical safety, you should call Police at 911.
There are two ways to report an incident. For general reports, you can fill out and submit the form found here: https://it.wisc.edu/reporting-an-incident-to-it-security/
If you need to report an incident of greater urgency, or if you desire a direct response to your report, you can call the DoIT Help Desk at 608-264-4357 to report the incident.