Contact sbcglobal cyber security department
I discovered this morning that I was subjected to a malicious "list linking" attack, i.e., I received approximately 150 individual emails, stating that I had signed up for their paricular email list. All signups originated from the same IP address. According to IP lookup, that address is controlled by sbcglobal.net.
How do I contact their cyber-security department to report this and have it investigated?