How does the billing works ?

The story is that I have itunes store credit I got this from redeeming itunes gift card. I decided to give some one an app and the app store charged my paypal account instead of charging my itunes store credit ! I called Apple they give me apologies about that and they said there is a problem in the system so we are going to fix the problem and we will issue a refund so you can rebuy the app.

With this problem in mind, I did the same thing a gain and the system suppose to be fixed now but sadly it is not. I called apple and waited 45 min trying to solve this problem and they told me that I cannot give a gift with my itunes store credit ! even though itunes allows the gift to be regifted so the answer is not correct!

The question is how can I solve this problem ?