I lost my SIM card and need to stop the auto payment
I was using AT&T's prepaid phone while I was in the states, but I left the country 6 months ago. I thought I ended the auto payment but it seems like I didn't (I've been getting charged every month). I need to end the autopayment but I cannot log into my account online. How can I end it? I'm in Japan, so if I can do it online, that would be more convenient because of the time difference and fee of the international phone call...