I bypassed the netzero software by putting firstname.lastname@example.org and my password in the Windows dialup network connection settings. If I used just my username or email@example.com, it didn't work. As an example, if your netzero username is shaggie, then you would use firstname.lastname@example.org in the dialup settings. shaggie or email@example.com wouldn't work.
Netzero changes the local phone access numbers occasionally and retires some of the existing ones. Their software would need to be used occasionally to see the latest functional local phone numbers.