Lululemon doesn't want customers reselling its products on eBay.

The issue has come to a head in recent weeks. Several customers told Business Insider they had been confronted by company representatives after attempting to sell items on eBay, and even more are complaining on the brand's Facebook page.

Many said they have been blocked from buying items from the company's website.

The policy is frustrating to customers because of Lululemon's stringent return policy, which only allows returns of unworn merchandise within 14 days of purchase, even if the item was a gift.

Lululemon acknowledged to Business Insider that it had indeed blocked certain customers from shopping on its website if it had noticed a "pattern of re-selling new product numerous times on an ongoing basis and at an elevated price point."

It also recently updated its FAQ page to include its policy on re-selling.

"We do not support the re-sale of new product, especially if it is at an elevated price point," the page now says.

Kristin, a customer who wished to only go by her first name, told us she was banned from Lululemon's online store for selling a racerback tank on eBay.

Both Kristin and her husband were loyal customers who have "closets bursting with Lululemon," she said. She decided to sell the item on eBay because it didn't fit and she had missed the return window.

Kristin says she was unable to persuade Lululemon to unblock her IP address from the online store, and felt the company treated her "like a criminal."

"They said we are welcome to shop in their stores, and in that case, I should have donated the item," she said. "But part of the appeal of purchasing Lululemon products is that it does hold resale value."

Because the Lululemon's strategy includes stocking very few items and selling 95% of merchandise at full price, many customers are willing to shell out for items they couldn't find in stores on secondary e-commerce websites like eBay.

Eric Lewis, founder of the blog LuluMen, said he was also chastised by the retailer for trying to sell a pair of pants he bought at a recent warehouse sale in Canada.

After the college student posted the pants online, he said a Lululemon representative phoned him to say his actions were against policy and he would be banned from its website if he continued selling items on eBay.

"Why is Lululemon targeting a student who is selling some used items on their own eBay account?" Lewis asked.

He estimates he's spent $10,000 on the brand's clothing in the past five years, but has sold fewer than 10 items on eBay.

The company eventually apologized to Lewis, saying they confronted him for attempting to sell a pair of $19 pants purchased at the warehouse sale at a mark-up.

A company spokeswoman told Business Insider that the policy is for the good of customers, and is meant to protect them from buying counterfeit products.

"Bottom line, if it doesn’t come from us, we can’t educate, we don’t know the history of the garment, and we can’t guarantee its’ authenticity," the spokeswoman, Alecia Pulman, said in an email.