The deal failed, and AT&T was forced to pay T-Mobile a $3 billion break-up fee, which TMo has used to build out their network.

http://arstechnica.com/gadgets/2012/02/t-mobile-takes-3-bill...

They then sold their towers for $2.4 billion http://www.bloomberg.com/news/2012-09-28/crown-castle-to-buy...

Looks, like something you do with office space financially.

The deal failed: http://en.wikipedia.org/wiki/Attempted_purchase_of_T-Mobile_...