I bought a pay-as-you-go SIM card when I traveled to Europe a few months ago, and I don't know when this SIM card will expire. I also can't find the store where I originally purchased the SIM card. Since returning from Europe, I haven't made any calls, used the internet, or sent/received text messages. However, I used it to register a game account, and I don't want to lose this game account. How can I ensure that this SIM card remains active?
