Coupang's delivery trucks are parked in Seoul, June 13. Yonhap

Coupang faces growing public backlash for threatening to suspend its flagship Rocket Delivery service, as the gesture is seen as an apparent power struggle against an antitrust watchdog, which consumers argue will end up harming their interests, according to subscribers of Coupang's paid membership, Tuesday.

Last week, the nation's largest e-commerce firm was fined 140 billion won ($101 million) from the Fair Trade Commission (FTC) for allegedly manipulating its algorithm to favor sales of products from its private brands.

Coupang counteracted the sanction with an immediate release of statements that the company will not be able to continue offering the super-fast delivery service to customers, saying that the fines will cause it massive inconveniences and losses.

But members for Coupang's Wow paid membership service said the firm's counteraction leaves much to be desired, as it appears to be holding customers hostage over the escalating tit-for-tat between the two sides.

"Coupang gives an impression of making use of customers to dodge the sanctions imposed by the watchdog," a user of Coupang's Wow membership said on condition of anonymity. "The company appears to be well aware that its millions of loyal customers will have to endure huge inconveniences from the potential service suspension."

Even if nothing specific has been decided over whether Coupang will actually stop operating the service in protest of the penalty, the gesture, in itself, is undesirable from the perspective of customers, according to the subscriber.

"Many Coupang subscribers around me feel unnerved after receiving the news," the Coupang subscriber said. "The company leaves an image that it threatens customers to capture a better position in the ongoing struggle against the authority."

Another Wow subscriber also expressed discomfort over the countermeasure from Coupang.

"Many customers have already been satisfied with the overall services from Coupang," the user said. "But the services are not free, and on top of that, the company will soon raise the fee. The company makes money with the service, so it should no longer confuse customers with such warning messages against the watchdog."

Chances appear very slim that Coupang will end up suspending the Rocket Delivery service, as most of its customers would likely switch to other services under the scenario. The unmatched delivery speed is the core strength of the company.

As of the end of last year, the number of subscribers to Coupang's paid Wow membership came in at around 14 million.