I have a kitchen company and there are occasional times when I give people the wrong price. with so many variables mistakes sometimes get made. I would have thought carpets would be a bit simpler but I guess they could still make mistakes. If the mistake I make is small and wont lose the company money I would just sell it at the lower price. However I do not legally have to.
Have a look at the extract below from trading standards consumer advice
"I saw a price on an item in a shop, however, the assistant refused to sell it at the price saying that there was an error. Can the shop refuse to sell at the price displayed?"
Yes - As with the goods on display, the shop is not obliged to accept your offer. However, it might be a criminal offence under the Consumer Protection Act 1987 to mislead consumers about the price of goods on display. You should report any occurrence like this to Trading Standards.