Wait, I don't get this. The Amex agent called the old phone number on the account. The person who answered gave some indication of being the account owner, but didn't answer quite as many questions correctly as the thief.
So what scenario is the agent hypothesizing? The person at the old number was actually the identity thief, and used the account for maybe several years without any challenge, before the actual owner changed the number back? That makes not the slightest bit of sense to me.
I think if the phone number has recently been changed, and you call the old number, and the person who answers can answer any question at all about themselves, you have to figure that's the account owner. Who else could it be???
So what scenario is the agent hypothesizing? The person at the old number was actually the identity thief, and used the account for maybe several years without any challenge, before the actual owner changed the number back? That makes not the slightest bit of sense to me.
I think if the phone number has recently been changed, and you call the old number, and the person who answers can answer any question at all about themselves, you have to figure that's the account owner. Who else could it be???