Vodacom App misleads clients

I played the mega shake. I was prompted to upsize my prize by purchasing 1G data plus 1GB data for 7 days. I pressed on the BUY option and immediately R59 was deducted from my available airtime without giving an option to confirm my choice. I phoned 082135 and the lady confirmed that if I used the USSD option I would have had a chance to confirm my selection, but using the app when you press Buy that is your confirmation. Also when prompted to buy, no amount is specified that will be deducted. As a consumer I feel cheated by a company without recourse to cancel or reverse this transaction.