Can't dial up on Verizon Broadband using my T500

[netcomrade]

I have a Kyocera KPC650 card, which works perfectly fine on my T43, so it's not an account problem.
A connection occurs, but I get a disconnect right away with an 'error 720'

Have re-installed software..
Have rebooted..
Have spent about an hour on the phone with Verizon..
Have even tried to pair up my laptop with Bluetooth on Blackberry, with similar results on dial up (but frankly, I never tried that before)

I could try to get a new modem out of Verizon, but
a) I am fond of the card, b/c I invested $200 into an external antenna with a booster
b) judging by my blackberry/bluetooth experience it might not even be an issue with hardware.

Any suggestions?