T-Mobile Attacks Dish Use of ‘Fabricated’ Data in Sprint Fight

T-Mobile US Inc. escalated its monthslong spat with Dish Network Corp. over the mobile provider’s planned takeover of Sprint Corp., accusing the satellite TV company of using “fabricated” data to say that the deal will raise prices for consumers.

Dish fired back, calling the charge “baseless and irresponsible.”

They’re fighting over whether T-Mobile’s $26.5 billion merger with Sprint will harm consumers by raising prices. Dish, which is pressing to enter the wireless market, is one of the deal’s biggest opponents, saying it will cause too much consolidation.

The clash between the two companies is playing out before the Federal Communications ...