After a complaint by rival T-Mobile USA (TMUS) that Sprint (S) was over-reaching in its advertising, the National Advertising Division recommended that Sprint stop making claims including having a "brand new," "all-new" or "America's Newest" network.

The ad industry's self-regulatory group also said on Tuesday that Sprint should stop saying it "is the most improved U.S. company in customer satisfaction, across all 43 industries, over the last six years."

Some other ad claims used by Sprint that are at issue include:

"Stay connected on America's Newest Network - HD Voice, Faster data speeds, fewer dropped calls."

"Sprint has an all-new network, providing customers across the country with significantly better call quality and faster data speeds in more places."

"America's Newest Network, built from the ground up."

Essentially, the National Advertising Division, which investigates advertising complaints, concluded that there is no way to evaluate Sprint's "newest" claims. Sprint argued, the group said, that rather than upgrade its old infrastructure as competitors did, it replaced its network.

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"NAD was not persuaded that a network could be termed 'newest' simply because its modernization efforts involved dismantling an old network as opposed to upgrading an existing network," the group said in a statement.

Also, Sprint can boast of improvements it has made, the NAD said, but should note that claims it makes about "faster data speeds," "better call quality," and "fewer dropped calls" should more clearly note that those claims are related to the Sprint's old network not the competition.

As for the improvement in customer satisfaction claim, the NAD noted that while Sprint's increase in customer service ratings since 2008 is bigger than that of any other company, its customer satisfaction ratings actually have declined in the past few years. That, the group said, takes away from the claim being meaningful.

Sprint, in its official response to the findings, said it would take the recommendations into consideration.