I got that notification by email yesterday
The email contained a set of alternative 3G / 4G plans from Optus, and a link to a coverage map. According to that map Optus have no plans to provide 4G. So I guess I will be migrating to Telstra. They already have 4G in my area and I have a line-of-sight to both Optus and Telstra. I plan to install an external MIMO antenna.
My guess is that in future years, this event will end up being a case study in Business Schools. Why would anyone pay $230 million for a business then shut it down without having an equivalent offering (read 4G) in place? The spectrum they acquired is all very high frequency and does not penetrate that well. Users needed to place modems near the right window or use an external antenna. The spectrum is not worth any where $230 million.
The other issue is who in their right mind would want to do business with a company that would likely cut you off in this way?