Claimed hack of entire T-Mobile US network data

The following has been posted by hackers seeking a reward, so far their claims have been unconfirmed but if true would be shocking.

"Date: Sat, 6 Jun 2009 15:18:06 -0400

Hello world, 

The U.S. T-Mobile network predominately uses the GSM/GPRS/EDGE 1900 MHz frequency-band, making it the largest 1900 MHz network in the United States. Service is 
available in 98 of the 100 largest markets and 268 million potential customers. 

Like Checkpoint Tmobile has been owned for some time. We have everything, their databases, confidental documents, scripts and programs from their servers, 
financial documents up to 2009. 

We already contacted with their competitors and they didn't show interest in buying their data -probably because the mails got to the wrong people- so now we are 
offering them for the highest bidder. 

Please only serious offers, don't waste our time."