Over the past year or so, T-Mobile has taken up the mantle of being the "uncarrier" -- the company that knows what mobile customers hate and aims to get rid of their biggest pet peeves. On Monday, the firm announced that it was tossing out another one of those irritants: domestic overage charges.

The changes go into effect in May, for the June billing period. T-Mobile had already eliminated overage fees on some of its plans, but Monday's announcement means that all customers who aren't already on unlimited plans will now have unlimited talk and text. Those who go over their data limits will see their Web traffic speeds throttled back but will not get a higher bill.

It's the latest in a series of unorthodox initiatives the company has launched in a bid to gain customers and set itself up as the service leader in a field that doesn't have a great reputation among its customers.  The efforts started a year ago when T-Mobile announced that it would separate the cost of users' devices from the cost of their data plans. The company then eliminated international roaming charges, simplifying charges for calls overseas and promising to buy customers out of their contract with the other guys. Last week, the carrier introduced a $40-per-month plan for bargain-conscious consumers, followed by an offer for customers to get LTE-connected tablets for the cheaper prices set for WiFi-only models.

All of these changes have earned T-Mobile goodwill among consumers and brought in more subscribers -- though at a price. The company reported in February that its losses grew to $20 million in the last quarter of 2013 even as it added a total of 1.6 million customers in the same quarter. Revenue for the firm increased 39 percent year-over-year to $6.83 billion.

The firm, whose proposed merger with AT&T was rejected by the Justice Department in 2011, has been the subject of several acquisition rumors. Most recently, it's been rumored that Sprint -- the nation's third-largest carrier -- is interested in its scrappy competitor. 

But in an official blog post, T-Mobile chief executive John Legere didn't say anything about an acquisition. Rather, he called on Sprint, AT&T and Verizon  to match T-Mobile's latest move in killing overage charges.

With his characteristic brand of candor, Legere also promised to keep up efforts to separate T-Mobile from the pack.

Imagine the smile on my face as I watch millions upon millions of Americans flipping the bird to the insanity and pain of the past and joining this consumer revolution – while I sit back and watch the competition flounder.

T-Mobile will never stop innovating this industry and advocating for America’s wireless customers.  We will always listen, speak up for you and stand with you. That’s my personal promise.

Shares of T-Mobile were down slightly from its opening price of $30.10 in afternoon trading, to $29.89 per share.