The wireless carrier said the stolen data includes the names , cell phone numbers , addresses , and birth dates of German subscribers . Deutsche Telekom said it lost personal data for about 17 million T - Mobile Germany customers in the spring of 2006 . Thieves got their hands on a storage device with the data , which included the names , addresses , cell phone numbers , and some birth dates and e - mail addresses for high - profile German citizens . The company said the records did not contain bank details , credit card numbers , or call data . T - Mobile Germany said it reported the data breach to prosecutors in 2006 , and that there was no evidence that the data had been misused by unauthorized parties . But the issue came to light when German magazine Der Spiegel said it was recently able to access customer information through a third party . " We are very concerned by the fact that the incident from 2006 is relevant once again . Until now , we were under the assumption that the data in question had been recovered completely as part of the investigations of the public prosecutors ' office and were safe , " said Philipp Humm , managing director of T - Mobile Germany , in a statement . " Notwithstanding the fact that the culprits have been at work with a tremendous criminal potential , we earnestly regret to say that we have not been able to protect our customer data in line with our standards . " T - Mobile Germany said it has taken multiple steps to shore up its security since the breach , including tighter restrictions on who has access to information , more complex passwords , and increased monitoring of security systems . Subscribers are encouraged to call a toll - free hot line if they 're concerned that their information has been compromised . ;