Deutsche Telekom said it lost personal data for about 17 million T-Mobile Germany customers in the spring of 2006. The data included the names, addresses, cell phone numbers, and some birth dates and e-mail addresses. The company said the records did not contain bank details, credit card numbers, or call data. Der Spiegel said it was recently able to access customer information through a third party. Subscribers encouraged to call a toll-free hot line if they’re concerned their information has been compromised.”]
Source: https://www.darkreading.com/attacks-breaches/t-mobile-lost-17-million-subscribers-personal-data

