Same here. Thought they left voice mail, cause I got an alert, but when I listened to it, there was nothing but dead air. If it wasn't important enough to leave a message, I don't need to hear what they have to say. They're blocked now.
Found someone on another site (http://mrnumber.com/1-312-800-9070) who said they called his cell and it was cruise related. On that note, it was my cell they called as well. I don't have a landline phone anymore, haven't had one for about 10 years.