I had to do this about a year ago - not for date of birth, but for suffix. AA systems don't properly handle suffixes, so with Jr. on my name, it throws everything off.

Advantage CS was the group that finally did it - I had to send in the passport pic as well. It took 4 or 5 times before I got an agent that actually figured it out - so as someone said above, just keep trying and stay on them until they get it done. It's a total pain, but worth it in the end.