Thanks for posting the Miami number. My wife decided to (finally) get the LG500g, and porting it over from her old 410g would not work online. They are both LG's, both AT&T sims, and it won't work, just like it wouldn't for me.
She's really looking forward to the CS experience once again.
Make the CSR varify that the actual SIM # and the SIM # in their system match. The last time I did what you are doing, it was 20 minutes start to finish.