Rang twice, hung up. It's not a problem, if you call me on my cell phone and you don't leave a message, I add you to my contacts list as "Ignore" which has a ringtone of silence. No need to get blocking or anything complicated like that, just setup a single contact that has a rington that is just an MP3 of no sound. I've been getting a lot of calls from random numbers lately, and they are all over the country. Looks like they are spoofing the caller ID.