MyNetFone is just a retailer. They have a service agreement with Symbio Networks for 5 years which see them buy termination from Symbio. The equipment that MNF subscribers connect to is in fact owned by Symbio which is privately owned and hence is a little harder to takeover.
If they did take over MyNetFone, engin couldn't make any cost/equipment savings as they have a binding agreement to buy termination from Symbio for another few years.
The MyNetFone business is the one selling adaptors for $9.95 with $10 call credit and free delivery.
I suspect it is the Symbio business that would have the potential to be more 'profitable'.
ENG Price at posting:
0.0¢ Sentiment: Buy Disclosure: Held