Things got ugly on Wednesday when T-Mobile CEO John Legere publicly criticized Sprint's new advertising campaign. He called Sprint's new "all-in" pricing plan "a swing and miss." Sprint lashed back out fast.
Sprint CEO Marcelo Claure fired back with an full-on Twitter rant, calling foul on T-Mobile's "uncarrier" plan and accusing the firm of lying to consumers.
Follow the nasty war of words below.
(Editor's note: Some of the tweets contain vulgarities that may offend some readers.)
When asked about the Twitter spat, Sprint defended its CEO's stance.
"Sprint's new all-in plan is all about straightforward simplicity, transparency and giving customers what they want in a way that is easy to understand," Sprint spokesman Scott Sloat told CNBC on Thursday. "Our competitors only claim to do that. Marcelo was just calling that out."
T-Mobile declined to comment beyond the tweets.