It’s always a nerve-wracking moment when your payment card is declined — you know the feeling: your pulse races as images of negative account balances dance in front of your eyes. But one Burger King customer in the United Kingdom had to suffer through that feeling not because she couldn’t afford to pay for her meal, but because the cashier tried to overcharge her… by more than $12,000.

The woman was with her son and daughter at London’s Luton Airport this week, and had ordered a Whopper Steakhouse burger, regular fries, regular soda, and two portions of chili bites, reports The Sun, for a total of £9.47 ($12.38 U.S. for those Americans playing at home) for the meal.

But when she gave the cashier her card, she was told it was declined, forcing her to scrounge up some cash from her two adult children. She didn’t realize what had happened until she got home and took a look at the scrunched up receipt from the first attempted transaction — and saw that the cashier had attempted to charge her £9,471.96 ($12,384.40).

“I went ice cold,” she said, and called her bank. She was told the charge had immediately been declined because it was abnormally large.

“But it rings alarm bells – if it was, say, £74, it would’ve gone through,” she says, adding that she’s learned to check the bill when she pays regardless, and to use the chip-and-pin system to verify the amount she’s being charged.

DON’T KEEP THE CHANGE Mum charged £9,000 for a meal with her kids at Burger King in Luton Airport [The Sun]