Block his number.

Get a .mp3/.mp4 or .wav file recording of any and all voicemails.

File a police report for harassment.

Inform corporate legal department so they are brought into the loop.

Blacklist the MFer with every operation you know.

Alternately,

Turnabout is fair play - scrawl "For a good time, call Destiny" with his phone number on it in every seedy truck stop and gas station bathroom you come across