I did the same thing one time just for the entertainment value. He wanted my Medicare number, so I read it to him with the digits all scrambled. I guess there must be a validity check one can run because he spotted it as a phony number right away. He still spent a half hour, which is probably their limit when making no headway, trying to get the correct number.
I just pretended to be unable to correctly read a series of digits. He was very frustrated at the end. It made my day.
Excellent work.