Truphone, a mobile VoIP entrant in the UK, that has developed a way to make cheap calls over dual-mode phones, reports GigaOM. A displeased T-Mobile has blocked the service from its network.
Truphone allows users to make cheaper calls with its VoIP client, which operates over dual mode phones such as Nokia N95 and Nokia E-Series phones.

The company is also launching a new and improved service, Truphone 3.0, which grants free text messaging and delivers VoIP calls over 3G phones. All of this has forced T-Mobile to take action.

According to M:Metrics, a whopping 86 percent of UK mobile users are also frequent users of SMS.

This isn't the first time Truphone has triggered the ire of mobile telecoms. A few months ago, the company was blocked by Orange and Vodafone. To combat Truphone, Vodafone introduced a new policy that makes it more expensive to use data plans for anything other than browsing and email.