Switching from Vodafone to Orcon; the process

So after a horrible day dealing with Vodafone's atrocious customer service I decided to look at other ISPs. I've settled on Orcon and I'm wondering what the switching over process is?

I need to get a VoIP modem from Orcon so assume this is the modem they send if you select the Home phone option on the sign up process?

Will my connection with Vodafone automatically be shut off or do I need to notify Vodafone to close my account?

It will take a few days apparently for the modem to arrive, in that time will I still be able to use the Vodafone account that I've paid for, even if the home number is being switched to Orcon?

Will the Geekzone Orcon deal ever come back? Would be good to know this before I make the change.

... anything else I need to keep in mind?

Thanks :)