Gigantic bill apparently reflected using 9.5 gigabytes of data on a phone that had not been set up for international roaming

T-Mobile told ABC: “We recommend our customers check the travel features of their plan, such as international data roaming, before departing …

if a customer is on an older plan that doesn’t include international roaming for data and calling, they’ll need to make sure they’re using airplane mode and wifi when using data to be certain the device doesn’t connect to an international network.”