The Advertising Standards Association (ASA) said it had received complaints from people about a TV ad offering a wireless laptop for £299.
But the complainants either couldn't find the laptop in the shops or were offered machines that cost more, said the ASA.
Comet claimed that when the TV ads were first broadcast, it thought they had plenty of stock, but found demand exceed supply.
The ASA said Comet had assured it that this type of thing would never happen again. The ASA reminded Comet to make sure TV ads pointed out limitations on availability. µ