Cell C theft or money making?

Today I went onto the Cell C App to try purchases Data on the one contract that I have with Cell C, I went under the phone number that I wished to purchase for and went through the process of payment which gave me the option on the Cell C App under the particular number I wanted to purchase for to use Instant EFT. I went through the steps again all through the App once I had purchase through Instant EFT secure line and the amount went off my bank account it took me back to the Cell C App which then said unsuccessful. I contacted the Cell C customer service again through the App and explained to the lady what had happened, she informed me that because the contract that I was wanting to purchase for is an open line that I can't purchase Data with instant EFT. I said ok that is fine we can do it another way but what about my monies that I have paid, to which she told me, "unfortunately you have forfeited that money" After letting her know that I don't agree with it as I did it through the App would should have not allowed me to have the option to purchase as I was under the contract in question as well as on the Cell C App. She spoke to her supervisor and came back with that it is a bank issue and not an issue with Cell C which I completely disagree with as I did it through the Cell C App and not through Banking App. So now I sit with no data and money out my bank account. Pretty much theft......