Paid for 12G got 9G staff reluctant to help

Bought from the app 12G anytime and 7G night the app shows I only got 9G and 7G. I sent in an enquiry it was esculated and then closed. I sent in another query as my satisfaction was not good. It's seems your staff needs training. I don't know how you can use 12gig data if you only got 9gig and the app shows you only used 9 ... my phone shows data usage well below I paid for. I paid for 12 I want 12 this is your add this is your app and I can show screenshots. How can staff not understand there was an error and get it fixed? It's baffling.