The data stolen, according to T-Mobile was the personal information of about 75 million prepaid customers. Records including name, billing address, phone number, account number, rate plan, and features.
So now approximately 75 million records are at risk for fraudulent activity.
If you received a notification, T-Mobile is suggesting you call and update your PIN/Passcode.
No financial data or social security number were stored on the breached servers.
It should be noted with the Sprint/T-Mobile merger looming ahead, that Sprint did it first this year, and in this case T-Mobile is following along.[T-Mobile]