Who called from 3218450000

They have been calling me for over a year.  They must have a long list of phone numbers they call from.  Every time I block them....they call from a different number.  Some times I will answer there call, and jack with them, and ask them all kind of random questions...to keep them on the line, in hope to increase there cost.....its funny, they hang up on me.

Did not leave a message. Number added to my BLOCKE list.

They called a few minutes ago. I Did not answer. They did not leave a message. BLOCKED number.

Didn't answer...left no message. I never answer calls from numbers I don't know....nothing good can come from it.

Called personal cell during work hours. I let call go to VM as usual with unknown numbers. No message left.