"My 14-year-old son brought in the mail today & was quite disturbed & fascinated by a 'gift' Lands End sent us—a copy of GQ magazine with an absolutely OBSCENE cover!!!" Sue Skindell Bauman wrote on the company's Facebook page.
"I was shocked and severely disappointed to receive such a magazine unsolicited. I had never expected to receive such a thing from a company with a caliber such as yours, and am saddened that I will no longer to be able to shop with you," Julie Doyle Baumgartner wrote.
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Lands' End President and CEO Edgar Huber issued an apology letter to its "valued school uniform customer," saying the issue was sent to all customers who spent more than $100 at the retailer from July 9 to 16.
"We are truly sorry this magazine was sent to you," the letter said. "There are simply no excuses; this was a mistake. Please be aware of the suggestive GQ cover and take the necessary steps as you and your family members check your mailbox in the next few days."
Huber said the company entered a year-long partnership with GQ publisher Condé Nast to "reward our valued customers with magazine subscriptions highlighting fashion and lifestyle topics."
Although Huber wrote that the company was not able to halt the issues that have already been mailed, it has removed all of its customers' names from GQ's subscription list, switching the subscriptions to Condé Nast Traveler.
Lands' End did not immediately respond to request for comment.
—By CNBC's Krystina Gustafson