I got a call from the number, like the others, no message. I, too, recently had Charter service installed. Either Charter is calling with a legitimate reason and stupidly not leaving a message, or they have sold my number to a third party sales division and they are "cold calling" me and will not leave a message.
In any case- Charter- If you are reading this, PLEASE instruct your phone people to LEAVE A MESSAGE. Those of us who are thorough with our lives will waste time trying to find out who called to determine if it is important.