T-Mobile's aggressive Uncarrier ad campaigns have drawn the ire of the National Advertising Division. The NAD, which works on behalf of the Better Business Bureau to "review national advertising for truthfulness and accuracy," says that some of T-Mobile's recent barbs aimed at rival AT&T have been "flawed." At issue are ads and commercials that state T-Mobile's network offers 50 percent more bandwidth than AT&T. But in making that claim, T-Mobile is focusing on AT&T's HSPA network, while completely ignoring its fast-growing LTE footprint. According to the NAD, there's no conclusive evidence showing that AT&T's overall network is slower or more congested than T-Mobile's.

The NAD is urging T-Mobile to stop with the blanket statements and get specific about regions and scenarios where it offers better service. But the wrist slaps don't end there. T-Mobile is also being asked to stop boasting that its network uses the "most advanced technology" and offers "faster 4G service" than competing US carriers. Under CEO John Legere's stewardship, T-Mobile hasn't been shy about slamming its larger rivals in the US wireless industry. Ad campaigns aside, Legere himself often relentlessly derides AT&T, Verizon Wireless, and Sprint via Twitter. T-Mobile certainly isn't alone in its iffy claims; Verizon and AT&T remain locked in a public feud, each vying for the honor of "most reliable" network.

Update: In a tweet to The Verge, T-Mobile CEO John Legere says that the NAD's findings won't result in "significant" changes to T-Mobile's advertising and marketing claims.