Trading standards officers in Derbyshire have intervened to support a shopper claiming discount vouchers from Littlewoods.
Littlewoods is waging war against "ineligible" voucher users
The catalogue group has angered some shoppers by demanding that an online discount voucher be paid back.
The money-off voucher was meant for a small number of specific customers, but spread virally on internet chat rooms.
The BBC has now learned that Tim Hill, from Derbyshire has been successful in keeping his £48.50 discount.
He told the BBC that the credit had been deducted by Littlewoods from his account almost two months after he used it.
Derbyshire Trading Standards took up Mr Hill's battle to uphold the discount he had accessed from a football forum.
A spokesman for Derbyshire County Council said: "This is a case where the customer used a discount code advertised on a third-party's website.
"Some companies state that if customers try to use discounts to which they're not entitled, they will be charged in full.
"But in this case the sale was made with the discount and the goods dispatched so the contract was accepted by the seller and we felt that a further charge shouldn't have been made."
A Littlewoods spokesman said he didn't know anything about the refund to Mr Hill and said he would pursue the matter.
Littlewoods has stuck by its tough line that discount vouchers which spread over internet forum should not be honoured because of its online terms and conditions.
It is demanding that a £25-off discount voucher issued in July be paid back to the UK web retailer by those who found the code on a money-saving or social network website.
Littlewoods says that the voucher was sent out as a flyer to a specific group of about 78,000 account holders as a gift for any inconvenience caused by the retailer's simplification of its data base.
Terms and conditions
Bargain hunters are furious at what they see as Littlewoods reneging on a contract of sale.
They are also angry that Littlewoods has taken over two months to pursue the alleged offenders, by which time they can no longer return the purchased items under the store's returns policy.
One aggrieved voucher user James Gosnold believed the situation had important implications for online trading standards.
He added: "Can you imagine buying something in a sale at High Street shop only to discover two months later that the sale price didn't apply to you? And that you didn't have the option to return the goods?"
But Littlewoods' position has been upheld by Liverpool Trading Standards, the home authority for the store.
The regional body's manager Allan Auty told the BBC that shoppers should make sure that they are legally entitled to the deals before they go ahead and use them.
He said: "In fact, if you think that the vouchers are not destined for you and you use them anyway, you could be breaking the law and it may not be the retailer knocking on your door, it could be the police."
One lawyer who spoke to the BBC on conditon of anonymity agreed with the argument that once an offer of payment has been accepted by a business and the goods dispatched, a contract has been agreed which cannot be broken.
Mr Hill said: "Littlewoods tried all sorts of tricks and told us different stories why they couldn't reinstate the discount, but eventually they added the £48.50 to my account."
He even received an email from a Littlewoods staff member offering "sincere apologies" for the inconvenience" he was caused with a confirmation of the credit.