I used to love hearing JC call in. He was such a nut job, and he was so outlandish that you knew you were in for a great time the moment you heard "I STAND INSULTATED, MR. BELL!!!!!!!" He really went nuts when Art mocked him with his devil voice. Noory didn't handle him nearly as well. Ian Punnett played him like a fiddle, though.
After reading this thread. I did a quick search and saw two appearances referenced since 2013. I didn't hear the clips but I think I heard one in 2017(?) after the call, George reassured us that it really was him. He needed to. Nothing reminded me of JC. Throughout an adult life, most people's voices stay the same in some way (tone, timbre, pacing) minus strokes.
I have these four JC calls from 2013-2015. There may well be others I don't know about.
2013-10-03 (GN) JC Makes Citizen's Arrest of Art
2014-10-31 (GN) JC Rants About Trick or Treating
2015-02-27 (GN) JC Rants About "50 Shades of Perversion"
2015-10-09 (AB) JC Calls MITD