ASDA is telling customers who cancelled their orders – having been hit by an online voucher error – that they may not receive their money back for 10 days.

As we reported yesterday, the supermarket giant was forced to apologise after thousands of online shoppers rushed to take advantage of a £75 off ‘e-voucher’.

Customers were shown an on-screen receipt confirming their purchases had been accepted with the massive discount – and some even received their shopping before Asda noticed.

The blunder has been put down to a keying error by an employee.

The supermarket quickly launched a damage limitation operation, texting and calling shoppers to say there had been a mistake and they could pay the full amount when their goods were delivered or cancel the order.

Sheepridge’s Lynette Milner was one of the shoppers who had money taken from her bank before she was contacted by the supermarket to cancel the order.

She said: “We’ve checked the account and the money has gone.

“The man from customer services said they hadn’t received it. Now we’re being told that it will be 10 days before we get the money we paid back.

“Their attitude is that they are not in the wrong, but we think it’s verging on fraud.”

The scale of the introductory offer to use the online service is thought to have attracted thousands across the country – not least with a big England game pending and more people bringing in provisions.

Ms Milner added: “We have been customers at Asda for 10 years and the way the people on the phone have spoken to us is disgusting.”

Asda have now categorically ruled out any breach of their website security, a prompt investigation confirming that a ‘keying error’ was responsible for the voucher becoming available to all.

They offered an apology and said it could never offer such a large discount.

Yesterday, a spokeswoman said the 10- day wait for the return of the money was covered in terms and conditions and it actually went into a holding account that could not be accessed by Asda.

Depending on who customers bank with, they may see a pending amount debited, but the money is in a holding account and is not ‘taken’ until the goods are delivered.

She added: “We clearly had a keying error that wrongly gave people a discount at the checkout online. We put that right within hours and there’s no concern about site security

“We’re bending over backwards to recompense the small number of shoppers who wrongly got offered the discount voucher. We’ll be giving them free delivery and a discount off their asda.com shopping.”