(GeekWire File Photo)

Dish Network is not happy with T-Mobile over its plans to shut down a network still used by millions of Dish’s Boost Mobile customers. In a letter to the FCC on Thursday, Dish blasted the Bellevue, Wash.-based wireless carrier for what it called anti-competitive behavior.

Axios first reported on the spat.

Dish acquired Boost as part of the merger between T-Mobile and Sprint, which was completed a year ago. T-Mobile sold Sprint’s Boost prepaid business to Dish as a concession to win federal approval for the deal.

Dish is relying on T-Mobile’s legacy CDMA network technology as it works to build out its own 5G network. But it will reportedly take several years to replace the old service and transition the majority of Boost’s 9 million customers.

Axios reported that Dish was expecting T-Mobile to shut down the CDMA network in three to five years, but that date is now looking more like Jan. 1, 2022.

“During its earlier life as the ‘Un-Carrier,’ T-Mobile championed policies that promoted competition, diverse spectrum ownership, and efficient spectrum use. How quickly things change,” Dish said in its letter. “Now, T- Mobile opposes measures that would help new entrants and smaller providers compete ….”

The letter notes that Verizon, with just 1% of customers still on the legacy tech, isn’t looking to wind down its CDMA service until 2023.

“T-Mobile’s filing is just its latest attempt to flex its power to thwart competition,” Dish’s letter added.

Update: T-Mobile responded to Dish’s complaint with a statement to GeekWire later Thursday:

“The phase out of 2G/3G technologies across the wireless industry is a natural evolution. In T-Mobile’s case, this transition is essential to the creation of the ultra-high capacity 5G network we have committed to deliver for customers and to the government. We all want to make sure no customers are left behind, and we are following a tried and true process to achieve that goal.

“Everything we are doing here is exactly consistent with the agreement that DISH made with us a year and a half ago, and we have been very proactive and transparent about the timing for this transition with all of our MVNOs, including DISH. We gave DISH notice in October 2020 for a January 1st 2022 transition – far more than the required 6 month contractual agreement.

“Our agreement with DISH is also clear that they are responsible for migrating Boost customers, just as we are responsible for migrating Sprint customers, and we are confident that DISH is already making plans to take good care of their impacted customers prior to the transition date. Given the advance notice that they received, just a small percentage of Boost customers should need to upgrade their handsets by the end of this year, and typically those customers would be supported with incentives and promotions to get their handsets upgraded.”

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