Johnni, try calling Nextel back and trying again during a less busy period. Try asking Level 2 about the static IP address -- they may be able to help.
Saturday is sometimes understaffed... Try midday during a weekday, or weekday morning. Say, a Tuesday morning.
Also, are you really sure you want a Hiptop? Please see Why BlackBerry?
. Also, there's lots more software for BlackBerry than for Hiptop now!