Vodacom Con you into running out of minutes

So I've run out of airtime in my smart L contract. Yet vodacom will not let me buy a once off air time top up on the vodacom app. Theyll only let me buy a recurring top up. This is basically such a con Vodacom. You let me buy one off data. Sms or transfer any of the above to any phone except my own. Your hoping I go out of my minutes to get a surprise big bill at the end of the month. What a Con you are really. This is shocking and this is a true policy that the house always wins. You're more scaley then a casino in fact. Can't wait to finish my vodacom contract after at least 13 years.