We use a vodacom usb internet device on our computer at home and use pay as you go airtime.
in Feb 2013 we bought 500mb, but the end of Feb2013 we got notification that 200mb would expire at midnight???? sure thing, 1 March 2013, we had no airtime, and had to recharge again.
I feel this is me of airtime. Does Vodacom do this to all their customers? No wonder they make so much money, they it!!