I think that a lot of numbers is now voip numbers and does not fall under ALL NETWORK.Can you provide more info in this regard, I've experienced a similar issue with their "All-Network minutes bundles"
What was the prefix of the number you got billed for?
I can call all cellphone numbers, also 0860 and 0861 numbers with the bundle.
If I call an (021, 011, 012 etc.) number that turns out to be VoIP, I get billed from my airtime.
This really sucks because these days you have no way of knowing beforehand.