Rogelio Villarreal knew nothing concerning the French jeweler Cartier, he stated, when an advert popped up on his Instagram feed final December. He clicked on it, perusing the pages of glitz and different luxurious gadgets, together with purses, watches and necklaces, every listed for 1000’s of {dollars}.

Then Mr. Villareal, who lives in Mexico, observed a pair of earrings: slender studded 18-carat rose-gold cuffs lined with diamonds, priced at simply 237 Mexican pesos, or about $13.

“I used to be amazed to see how a lot the necklaces price and so forth and I stated: ‘Sometime,’ till I noticed the earrings,” Mr. Villarreal, 27, wrote on social media. “I swear I broke out in a chilly sweat.”

He purchased two pairs. Later, the value for the earrings was adjusted on the Cartier web site to 237,000 pesos — greater than $13,000.

The acquisition initiated a monthslong tussle between Mr. Villareal, a surgical procedure resident from the northern state of Tamaulipas, and Cartier, with a whole bunch of social media customers following alongside — some cheering, others taunting — and even a Mexican senator weighing in on the dispute. However Mr. Villarreal stated on Friday that he had obtained the earrings for the steeply discounted value and famous that he had a particular individual in thoughts to be their recipient.

“I’m excited,” he stated, “particularly for my mother. These earrings are for her.”

The candy deal didn’t come with out some resistance.

Inside per week of the acquisition, Mr. Villarreal stated, Cartier started a sequence of makes an attempt to cancel the order, initially saying that the earrings weren’t accessible.

When Mr. Villarreal made no transfer to cancel the order, he began receiving cellphone calls from firm representatives.

He stated they informed him that “the earrings that I had ordered weren’t on the appropriate value, which is why they wished to cancel the acquisition, and that due to the inconvenience they might give me a present.”

As “compensation,” the corporate then provided “a gesture from the home of Cartier” — a complimentary bottle of Cartier Cuvée champagne and a leather-based Cartier merchandise, in accordance with an e mail despatched to Mr. Villarreal.

He determined to reject the items and battle again, utilizing a contact type on the corporate’s web site to quote a federal consumer protection law in Mexico that claims {that a} items provider could be taken to courtroom “by not respecting the phrases and circumstances beneath which” a services or products is bought.

Cartier has not responded to a number of requests for remark.

Mr. Villarreal discovered the terms and conditions for gross sales on Cartier’s web site in Mexico, which state that any dispute may very well be dropped at the Workplace of the Federal Prosecutor for the Shopper for “conciliation.”

So he did simply that. He filed a criticism with the Matamoros department of the federal shopper safety company.

The company, which has a job much like that of the Federal Commerce Fee in america, has a historical past of intervening on behalf of shoppers when retailers change record costs after a sale.

In February, the buyer company invited shoppers to hitch a class-action lawsuit against Sony, which had canceled orders for a PlayStation 5 console that it had provided on its web site in Mexico for a 30 p.c low cost.

The buyer safety regulation is so well-known in Mexico that folks use social media to attract consideration to inaccurate costs on Amazon and different retailers’ web sites in posts which are extensively seen and shared, according to El Economista, a newspaper in Mexico Metropolis that covers monetary information.

Mr. Villarreal stated that the buyer company had summoned Cartier for arbitration and that the federal government had made a number of makes an attempt to mediate an settlement. Company officers stated they may not share details about an open case with anybody apart from the events concerned.

If the buyer safety company finds that an organization is at fault, it may possibly impose fines or different penalties, however it may possibly’t pressure an organization to abide by a value it listed, stated Jorge López Zozaya, a company lawyer in Mexico Metropolis. If no settlement is reached, both social gathering can ask for a decide to resolve the criticism.

Mexican regulation doesn’t prolong protections to shoppers if a listed value was clearly a mistake, Mr. Zozaya stated.

“If this case had gone to a courtroom of regulation, it in all probability would have resolved favorably for Cartier,” Mr. Zozaya stated.

However there gave the impression to be a truce within the matter. Forward of a shopper company mediation listening to subsequent week, Mr. Villarreal stated on Monday that he had obtained discover from Cartier that his order could be fulfilled, after which introduced the earrings’ supply on Friday. The settlement couldn’t be confirmed with Cartier or the company.

“Conflict is over,” he wrote in English in a social media put up on Monday.

Mr. Villarreal stated on Friday that the earrings arrived, and he shared a photo of two small packing containers wrapped in paper with wax seals. “As soon as upon a December,” he wrote within the social media put up.

Some customers applauded his tenaciousness in getting Cartier to adjust to the phrases of his buy, whereas others, together with a Mexican senator, had accused him of abusing the buyer safety system for his personal acquire.

“It’s fallacious to benefit from a mistake to the detriment of one other individual,” wrote Lilly Téllez, a senator from the state of Sonora, including, “even when the regulation helps you.”

Mr. Villarreal stated that he was glad that the ordeal was over and that he would signal an settlement to settle his criticism with the buyer safety company.

Elda Cantú contributed reporting from Mexico Metropolis.