Sainsbury's customers said they have stopped getting discount offers on their Nectar card accounts.
Shoppers have been complaining about not be able to build up points as quickly as before.
The supermarket chain has apologised to shoppers and said they are "personalising" Nectar card offers.
Some customers may find when and how often they get their offers changes over time, they added.
The supermarket revamped the Nectar loyalty scheme in 2019 to give shoppers weekly, personalised bonus points based on what they usually buy in store.
But some customers have complained that they have not had any new deals in weeks.
One person said: “For the second week running I've had no Nectar bonus offers for Sainsbury’s.”
Another tweeted: “No Nectar offers this week, so taking my shopping trip elsewhere. No explanation and loyalty schemes work both ways.”
A third said: “What the hell has happened to my weekly Sainsbury’s offers? Haven’t had any in two weeks now!”
Others have shared screengrabs from the Nectar app, which shows the message: “You don’t have any new Sainsbury’s offers at the moment, please check back again soon.”
Both changes to the Sainsbury’s website and Nectar app occurred between April 16 and April 19.
Shoppers who continue not to receive offers, and want to check if there is a problem with their account, can contact Nectar directly through the live chat on its website, by phone on 0344 811 0811 or via Twitter.
@nectar Have Sainsburys offers been retired? I haven’t had any for 2 weeks (only partner ones 😭😭😭)
— Emma Lovgren (@emmahasredhair) April 21, 2021
A spokesperson for Sainsbury's said customers should start receiving offers again soon.
Nectar has around 18 million customers and can be used in multiple stores and online retailers, such as Argos and eBay.
Through the scheme, you build up points which can then be turned into vouchers - one Nectar point is worth 0.5p, which means 100 points would convert into 50p to spend.
A Sainsbury’s spokesperson said: “We regularly review the promotions available through our Nectar app to ensure customers are always receiving personalised, valuable offers.
“As part of this process, some offers may be currently unavailable for a small number of customers and we apologise for any inconvenience.”
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