Josh Miller/CNET

Remember those Sprint ads where customers would take chainsaws and swords to their cell phone bills? You won't be seeing those anymore.

Sprint's ads enticed you to switch from your current cell phone carrier with the promise of a similar plan for half the cost. T-Mobile, the nation's third-largest wireless carrier, challenged Sprint's claim to cut your phone bill in half. The National Advertising Division, a self-regulatory council for advertisers, found that Sprint wasn't making its basis for comparison clear enough, and recommended the company fix the ads or stop airing them.

T-Mobile's main point of contention stemmed from the implied claim that you could get 50 percent off of any T-Mobile plan by switching to Sprint, the claim only applied to specific T-Mobile plans. Sprint had fine print specifying the details, but the NAD found that wasn't enough. T-Mobile also took issue with Sprint's $36 activation fee per line not being included in the ads.

"We called Sprint out on their total BS promises of savings that consumers simply wouldn't get," said T-Mobile in an emailed statement. "We're very pleased with the NAD's ruling."

The NAD's decision applies both to TV spots, as well as similar in-store advertising. During the course of the NAD review, Sprint notified the NAD that it had permanently discontinued the ad and agreed to comply with the council's recommendations.

Sprint supports the self-regulatory process of the NAD, the company said in a statement Friday. Sprint added that it was "pleased with NAD's conclusion that print and Internet advertising claiming 50 percent savings over most T-Mobile Simple Choice rate plans is truthful and accurate."

Updates, 11 a.m. and 3:43 p.m PT: Adds comments from T-Mobile and Sprint.