Caller ID Unavailable

As a person that just has to know all she can, that the caller id on my cell phone is not working properly is driving me rather crazy. So, tonight when my phone rang and (of course) the caller id displayed 'unavailable,' and there was silence on the other end, I spent a good fifteen minutes wondering (hoping?) who it was. I wondered what they wanted. If it was a wrong number. I wondered a lot of things. It would have been nice to have an identified call. Then I would have known which number to call back... I wonder why the caller id on my phone isn't working so well these days. I think I shall be calling Verizon tomorrow to have them fix that, if not for the convenience aspect of it, but just so I can know.