Debenhams has told customers that they have until Sunday, 20 December, to use any gift cards or vouchers they have.
After that date stores will simply stop accepting them.
"We will only be accepting Debenhams gift cards and e-gift cards in store and online until midnight Sunday 20 December," an email to customers reads.
It goes on to warn people trying to combine different rewards and vouchers that they can only use two at once.
"Please note you can make payment using a maximum of two different payment methods per transaction, which includes gift cards and beauty club rewards" it adds.
"To complete your order you must be able to cover the full amount with your chosen payment methods."
Debenhams is currently running a closing down sale in stores and online, with up to 70% off items as it prepares to permanently shut its doors.
The 242-year-old retailer, which began liquidation procedures on December 1, has launched its final ever clearance, as administrators look to shift stock before the business disappears for good.
Debenhams, which is known for its Blue Cross sales, had already launched a 70% off "fire sale" earlier this month.
But now the event has been rebranded as a "closing down" sale - with some items reduced to up to 80% off.
The sale is available both in store and online, with Debenhams' physical shops having reopened in England on December 2.
Hilco, which is managing the liquidation process previously told The Mirror that "UK operations will close" if no new offers for the chain come forward.
As such, stores will only remain open long enough to sell off what stock they can.
"Debenhams will continue to trade through its 124 UK stores and online to clear its current and contracted stocks," a statement issued to The Mirror read.
