Engen app ...WHERE DID MONEY GO !!!!

I am so upset,I topped up my engen 1 app card with R500 ,bought goods worth about R40 and in 2 days when I wanted to use my money it was not reflecting on the app. I had to leave the garage store so embarrassed because it looked like I did not have enough money to buy bread!!!! I called the online customer service,sent them the proof of transaction for the R500 from my back account to the app,but they are giving me a run around. The app only shows transactions from 2 months ago. All im being told is that its been escalated and over the phone I can here people talking,they don't want to interact with me again and asking someone else to take the call and tell me that they are busy on the other lines!! I have always liked engen but this is terrible customer service and at this point I hate it and would not advice anyone to use it!!!