JPMorgan Chase & Co canceled a question and answer session on Twitter with veteran investment banker Jimmy Lee after being flooded with insulting questions less than 24 hours before the session was to begin. “Bad idea! Back to the drawing board,” spokesman Brian Marchiony said by email on Wednesday evening. JPMorgan had started promoting the session with Lee, a vice chairman and deal rainmaker at the bank, last week on the social media site. The company had asked Twitter users to send questions marked with the hashtag #AskJPM in advance.