Paying for Google Apps is a crazy idea
I read their support agreement for paying customers, and it states they are not obligated to give you support for non-core Google services. This means you trying to get support for anything other than Gmail, Calendar, Groups, Talk, Docs/Drive, Sites, Video, and Contacts you may be SOL.
http://www.google.com/apps/intl/en/terms/tssg.html
One thing I remembered were users recommending the author of this submission to get Google Apps for support.
http://news.ycombinator.com/item?id=4676854
However, Google Voice is explicitly one of the services they list in their "additional services" that is not included in the support agreement.
I was planning to pay for Google Apps just for the support, but it just seems like a crazy idea.