Now the Allmänna reclamationsnämnden (ARN) has determined that since the electricity prices during the days around September 22 were around SEK 7-8, the customers should have understood that it was wrong, and therefore they say that the agreements that were concluded are invalid - even though several customers had get confirmation in the email.

"In this case, the assessment was made that it is common knowledge in society that electricity prices are high and that the price, which corresponded to approximately one percent of the correct price, was so low that the consumer should have understood that it was incorrect," writes Marcus Isgren, ARN's director, in a press release.

Just over 1,000 new customers managed to join the bargain prices before Skellefteå kraft had time to discover the system error.

Hear from Nina Munter, press officer at Skellefteå kraft, about what went wrong:

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Skellefteå kraft offered shockingly low, but incorrect electricity prices during Thursday morning.

Hear Nina Munter, press officer at Skellefteå kraft, about the mistake in the clip.

Photo: SVT, TT