Seriously flawed service. Shame on AT&T

My son is traveling with an AT&T GoPhone. I've been topping it up about once per month. Suddenly yesterday they won't apply the funds because they need some approval. They don't accept overseas calls (I''m not in the states). I've tried using my calling card, which comes from within the states and they don't accept calls from that number either. My son has fallen ill, doesn't have a working phone, and AT&T has got a lot to answer for. Seriously flawed  service. Utter crap.