Repeat caller - no message only says Plano in Caller ID screen. I block all calls from repeat callers with this pattern of no id. Most callers don't call back using the same number and don't leave a message if it goes to phone recorder. If I blocked every caller I get like this I would have hundreds of blocked numbers by now so I only block the repeat offenders using the same number to call back on.
The worst offenders are "clothing collectors". Some people say that these people are collecting for veterans but have no evidence of any $$ amount ever given to veterans group - they collect the clothing for free and sell it in second-hand stores.