Calls every night around 7:30.

One thing that does help is using the "Vacant Number" special information tones on the beginning of your machine message. That's the three beeps you get when you call a number that is out of service.

 Most robo call machines will recognize these tones and remove your number from their list. The catch is, however, that the beeps must be the first thing the robo caller "hears"  and some voice mail service add a message  before playing the outgoing message.

http://home.comcast.net/~mcbrides9/sit.html

Call on cell phone, rang twice, call ended.  Have blocked the number.

Called my cell. I don't answer unknown numbers.

do not know any from there