Toys R Us told US Internet shoppers on Wednesday that it would not be able to fulfil any orders placed after 9 December in time for Christmas Day.
But the US toy retailer said it would distribute $100 coupons to shoppers who had purchased gifts on its website in anticipation of the holiday.
A spokeswoman said: "Due to the volume, Toys R Us has been doing as many transactions as we can, but could not get through all the orders. We anticipated volume, but it went up so dramatically that it was beyond anybody's expectations."
She added that the glitch would only affect a small percentage of online shoppers, who have already been notified by email, but would not disclose what the percentage was nor how the $100 giveaway would affect the firm's bottom line.
Toys R Us had posted a notice on its website, toysrus.com, noting that its number one priority was to process existing holiday orders. It also recommended online gift certificates and visiting the stores as gift giving options.
But despite its problems, according to Nielsen/NetRatings, a research firm that tracks website traffic, toysrus.com was the sixth most popular Internet retailer from 1 November to 19 December, based on peak traffic levels.
And seven of the 20 most heavily visited online shopping sites during the week that ended 12 December were offshoots of brick and mortar chain stores.
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