AMNA NAWAZ: The words Cartier and bargain are almost never said in the same breath.

But the legendary French jeweler has been forced to extend an enormous discount to one man after he claimed an error allowed him to buy two pairs of earrings for just $28 that were supposed to sell for nearly $28,000.

Ellie Pitt of Independent Television News has more.

LEYLA HAYES: Designer jewelry doesn't come cheap, unless, of course, you find it online for much lower than it should be.

That's what happened to Rogelio Villarreal, who was browsing Cartier's Web site when he started these diamond-encrusted earrings for 237 Mexican pesos.

That's around 11 British pounds.

He bought two pairs, who wouldn't, before the price was quickly corrected to 237,000 pesos, or just over 11,000 pounds.

According to Rogelio, Cartier then tried to back out of the deal, but he asked Mexico's Consumer Protection Agency to get involved, and they ruled in his favor.

So how did he do it?

Well, Mexican consumer law requires businesses to sell their products at their listed price.

If they don't, customers can file a complaint and send proof that they bought it at that price, but haven't received it.

At this Central London jeweler's, they say there's no doubt he got a bargain.

DANIEL CLUNN, Harmony Jewels: You are paying for the brand name, you know?

Like when you walk into somewhere and you leave with a Cartier ring, there's that brand history.

You're paying a little bit for prestige.

I mean, he got very lucky.

I'd like to see his lottery winnings as well, because I wish I had a chance like that.

LEYLA HAYES: Cartier haven't commented, but the earrings finally arrived at a discount of around 29,500 pounds.

And Rogelio was more than happy to show them off.

AMNA NAWAZ: And that was Leyla Hayes reporting from Independent Television News.

GEOFF BENNETT: Talk about a discount.

AMNA NAWAZ: Right?

(LAUGHTER)