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