A Kmart customer has shared a worrying receipt scam that may have already affected thousands of shoppers.

Sharing the details on a popular Facebook page, shopper Amanda revealed how she had discovered the scam when she went to her local store to return some products.

After realising she’d left her receipt behind in a shopping trolley in the belief she wouldn’t need it, the Sydney mum used her internet banking statement to prove her purchases.

It wasn’t until a member of Kmart’s customer service team looked up her transaction that they made the discovery that someone had already returned all the items on her receipt.

It’s believed the scammer found Amanda’s discarded receipt and collected the items listed on the docket before returning the items at the Kmart service desk and asking for a refund.

“Customer Service at Kmart are happy for me to share a nasty experience today,” Amanda wrote on the North Shore Mums (Sydney) Facebook page.

“On Thursday, I purchased a number of items, including five boxes of coat hangers at $10 a box.

“On the way out of the store, I showed the exit attendant my proof of purchase and threw the receipt into the trolley (where it stayed).

“I realised I had no receipt when I returned today to bring back the coat hangers (my hubby bought same from IKEA) so went to customer service and showed the transaction on my internet banking – which they matched on their computer,” she continued.

“The Kmart refunds lady informed me that I had already returned all my purchases that day in the Bondi store.

“Turns out, somebody picked up my receipt – walked around Kmart collecting the same items, and then took them for a refund!

“It’s a real thing! She promised to share the store manager’s findings when they review the video of the Bondi store.”

Fellow shoppers were shocked by her story.

“The amount of times I’ve accidentally left my receipt in a trolley or in a bin without even thinking,” one said. “Never again. That’s just shocking.”

Another said: “I always see people’s receipts in the bottom of trolleys. I wonder how many people have been scammed and never even knew?”

Image: Facebook