Just days before Christmas, he received an email from the top US consumer electronics chain informing him that his online order for a 42" Samsung TV will not be fulfilled.

“You can count on me not being a Best Buy customer anymore,” Nenon told Reuters on Friday, adding that he was disappointed that the chain tried to make him buy an older model at the same price as a replacement, rather than trying to make amends for its shortcoming.

Best Buy is not the only retailer causing problems online this Christmas. Other brick-and-mortar chains including Target Corp, Wal-Mart Stores and Barneys are struggling to keep up with online demand, an indication of poor execution by retailers during the biggest selling season of the year.

“Since Best Buy's website has always been a stepchild to the stores, it's gotten short shrift, and when they boosted Web demand by essentially matching others' Web prices, they got a bit overwhelmed,” said Craig Johnson, president of retail consulting firm Customer Growth Partners.

In an email, Best Buy spokeswoman Lisa Hawks said less than 1 per cent of Best Buy customers' online orders during the Thanksgiving weekend and the following week were affected.

“The challenges related to this situation are being addressed. We are very sorry for the inconvenience this has caused, and are providing e-Gift Cards to the affected customers,” Hawks said.

Other chains apologized for online ordering and fulfillment issues as well.

“We, at Barneys New York, are sincerely apologetic for any inconvenience that occurred while holiday shopping on barneys.com this past week. We are personally reaching out as quickly as possible to every customer who has been affected by this limited, but unfortunate, IT glitch,” Barneys posted on Facebook. A spokeswoman for the company did not return phone messages seeking comment on the nature of the problems.