These restrictions will affect both new and existing customers, and will ensure an improved quality of service for all of our mobile internet users.
T-Mobile will not charge its customers additional rates for exceeding these data limits, and those who do will still be able to access important services such as email and website browsing, but will have file downloading restricted. Customers who have a need for higher volumes of data will be encouraged to take up a separate mobile broadband plan. We are confident that these changes will result in a better experience for all of our customers who use internet on their phone.Via T-Mobile Forums Check out TMobile's twitter for support and help
Now the 3 network's One Plan and Giff Gaff are the only networks providing unlimited internet. Giff Gaff which is operates on the o2 network provides internet with an FUP(Fair Use Policy)