This number calls my Dad's landline a few times a day. They never leave a VM. They are wasting their time because this is essentially a non-working number. We get so many junk calls we permanently keep the ringer off.
I can't find out any info about these jerks so if it keeps up I'll just block the number. Which I know will only be a temporary solution as they'll just start calling from another number.
I do get some satisfaction from the fact that waste their time calling, knowing we'll never answer.