STRATFORD, Ont. - The sale of a shoe worn by pop star Justin Bieber has hit a snag.

The high school auctioning the sneaker on eBay thought it had sold for US$5,500 Friday, but later learned the winning bidder forgot to ask her mom if it was OK to buy the shoe.

Keith Edwards, a teacher at Stratford Northwestern Secondary School, said the Edmonton girl's mother "probably had a moment of panic" after receiving the invoice for the autographed shoe.

There were 69 bids submitted for the scuffed right shoe, which has gravel in the tread and dirt on the side and comes with a letter of authenticity, before the auction closed Friday afternoon.

The teen star from Stratford, who is in England on tour, donated the purple size 7 1/2 Nikes to help his former school raise money for a broadcasting and communications studio. The school hasn't decided what to do with the left shoe yet.

Since the auction started March 1 -- Bieber's 17th birthday -- bids came in from across Canada, Australia, the Netherlands, Poland, England and the U.S.

By Thursday, there were bids as high as $12,400, but some weren't valid.

EBay Canada spokesman Kevin Wolsley said Friday that efforts were underway to resolve the sale.

"There may be a problem with the actual winning bidder on the listing," said Wolsley. "We're stilling working through that to determine whether the actual winning bidder is or is not going to come through on the sale."

If the winning bidder cancels the sale, the school can offer Bieber's sneaker to the next highest bidder, who offered $5,400.

Edwards said he wasn't sure what will happen next. The school, which had aimed to raise $3,000 with the sale of the shoe, is closed for March Break next week.

A lock of Bieber's hair enclosed in a Plexiglas box and signed by the singer was bought at auction for US$40,668 earlier this month by the online casino GoldenPalace.com.

Proceeds from that auction went to a foundation that provides a safe haven for farm animals.

On Monday, a pair of Bieber's shoes will go on display at the Bata Shoe Museum in Toronto following a tribute performance.