Credit card relief, got to be a scam as they did not know which credit card, yet their explanation was they had been monitoring my credit card

No message.

Just got a call on my cell from this number. No message left. My trucaller app said it was from a Cecil Carter.

Just got a call from this number. Picked up as I like to mess with these people, plus my voicemail gives them an equally good indication that it's a valid number. I picked up on the third ring, and it was a recorded voice that said, "I'm sorry, that is not a valid extension." Then if hung up on me.

Same here.  BLOCK these MOFOs.  iPhone has a built in blocker...fantastic!!!!