This number keeps calling my landline. Number called again and this time I was home to answer it and there was no one on the line, called the number back and it said "the number you have reached is not in service".....I blocked the number so they can harrass someone else.

they are calling to install solar panels

Not TTT.   some scammers selling solar panels.  Number has been disconnected.

This number calls often and no one is there! Very irritating.

How can a number call you and also be a disconnected number...? Extremely Irritating!!! Blocking Number Now. I think it is a Solar Panel Company... These people need to stop pestering people...