While it is true that if you cease to make payments on a GoPhone account, the account will close after three months, it sounds like you had auto-renewal set up. Auto-renewal automatically applies payments using your credit card information to renew your GoPhone plan. I recommend that you reach out to ATTCustomerCare via private message by clicking here. Be sure to include your name, your email address, and the GoPhone number that you had while you were here visiting. They will absolutely do everything they can to sort this out. You can expect a reply within two business days, so keep an eye on the little blue envelope icon at the top right corner of your screen.
Let me know if you have any additional questions!
*I am an AT&T employee and the postings on this site are my own and don't necessarily represent AT&T's position, strategies or opinions.