The Canadian company said it will continue to provide service and support to existing customers on T-Mobile's network or those who will buy products from the carrier's inventory.
"Regretfully, at this time, our strategies are not complementary and we must act in the best interest of our BlackBerry customers," BlackBerry Chief Executive John Chen said in a statement.
BlackBerry said it is "working closely" with other carrier partners to provide users with alternatives should they decide to switch from T-Mobile.
The relationship between the two companies soured after Blackberry's CEO criticized T-Mobile for sending out emails to some of its customers in February, pitching free iPhone 5s (Pictures) and touting the promotion as a "great offer for BlackBerry customers.
This sparked an uproar on social media forums after some of the telecommunications company's loyal BlackBerry customers reacted angrily to the offer, which they perceived as a slight.
The backlash prompted T-Mobile U.S. Chief Executive John Legere to respond publicly, assuring Blackberry and its users of his company's support.
T-Mobile could not immediately be reached for comment outside regular U.S. business hours.
BlackBerry, a one-time pioneer in the smartphone industry, has been struggling to claw back market share lost to Apple Inc's iPhone, Samsung Electronics Co Ltd's Galaxy devices, and other smartphones powered by Google Inc's Android operating system.
© Thomson Reuters 2014
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