A lot of social media users have reported receiving technical support, Facebook, donation, and social security, and bank telephone scam calls from 866 area code telephone numbers. Please see the comments below, if there are any. If you have calls from area code 866, please share your experiences with me by leaving a comment below. Area code 866 is a toll-free area code reserved for future use in the United States and Canada, but it seems as if it's currently in use or being spoofed. That is why it is always better to check an unknown phone number on a reverse lookup service (such as Information.com) before you call them back.