Do you get weird calls on your cell phone?

[bombastic]

First there were telemarketing calls, then calls about expired factory warranties. All of a sudden, I'm getting calls from 813-111-111 among other odd telephone numbers. If I redial, the number cannot be reached. My service provider claims to be unable to do anything to identify the origin of the calls. Short of changing my number, what can I do to stop these nuisance cell phone calls?
Some calls also come from this bizarre no: 50495581240. What could this be?

 

[mrfixit]

You could add them to your reject list.