Defective app defaults

I used standard bank app today to buy airtime (I'm with private banking). It seems the app defaulted to cell-c provider, and since I scrolled down to enter R200 amount, did not see this (I have 8ta). The app happily informed me my order was completed and deducted R200 from my account. Since it defaulted to cell-c carrier I never got the voucher. Immediately called private banking and after talking with 3 different escalation techs still getting a 'sorry there is no way to refund your money, or provide you with a useable voucher'. Essentially money taken out of my account , but received no service (and no way to get my money back). I think it's shocking that due to poor app design I should be penalized! Either want a refund or a working voucher please, but this is tantamount to *****ing.