Exercise patience OP. It works wonders! Keep in mind that like any other lender, AmEx has certain verification protocols they need to go through when processing any application, regardless of whether any "expediting" of the process was submitted or endorsed by the agent.
So, while it's doubtful they'll deny the application, if you keep calling it can also arouse a sense of suspicion.
I had a scenario that involved the 14-day pending/processing message not long ago. Eventually, once things were sorted out internally, AmEx reached out to me. But, I simply let the process take its course.