Walmart has admitted a technical issue for several days in mid-March resulted in the retailer overcharging customers in the United States.

The glitch  that started on the evening of March 19 prevented price data from flowing to self-checkout kiosks at 1,600 of its 5,000 US stores. 

The issue lasted for days and resulted in the company overcharging customers on thousands of items including food, clothes and appliances, according to Bloomberg. Some items also cost less.

Walmart has not said how many shoppers were affected, but – given it has around 37 million customers a day –  it is thought several million were hit. 

It comes as Walmart earlier this year settled a totally separate $45 million class-action after it overcharged for certain packs of meat and citrus fruit. Customers can claim up to $500.

A spokesperson for Walmart said that once it discovered the problem with overcharging at self-checkout kiosks i March it tried to work out which customers had been affected.

‘We’ve made it a priority to refund customers who were overcharged, and we did not take action on the undercharges with our customers,’ a spokesperson told DailyMail.com.

Walmart did not say how many customers it has refunded.  It also did not say how many shoppers or products were affected in the first place, nor why it was just at self-checkouts.

A legal expert said any overcharges – if verified – would have broken state and federal consumer protection laws. 

Christopher Peterson, a former attorney with the US Consumer Financial Protection Bureau, told Bloomberg incidents of overcharging would be ‘clearly illegal under the consumer protection laws of just about every state and the federal government’.

Since the pandemic, Walmart has invested billions of dollars in upgrading its stores and the underlying technology that powers thousands of its retail operations. 

In October last year, it said it would invest $9 billion in US stores including adding more self-checkout options.

It has not always gone smoothly. In February, the Wall Street Journal reported Walmart suffered an outage where thousands of registers were not able to process transactions, while Bloomberg reported on Wednesday the company also endured a glitch with its photo and vision centers earlier this year.

In January, Walmart agreed to pay $45 million to settle a class-action lawsuit in Florida alleging it overcharged shoppers for bags of citrus fruit and some meat, poultry and seafood products sold by weight. The company denied any wrongdoing.

Customers who were overcharged can claim up to $500  – here is how. 

The products will span frozen, dairy, snacks, beverages, pasta, soups and coffee

Walmart  in early May launched a new private-label food brand with most of its products priced under $5. 

The brand, called bettergoods, will hit Walmart stores and online with 300 products by this fall. 

The products will span frozen, dairy, snacks, beverages, pasta, soups, coffee, chocolate among others, the retailer said.

It will be Walmart’s biggest store-label food brand in 20 years in terms of its breadth of items, as it seeks to appeal to younger customers who are not brand loyal and want chef-inspired foods that are more affordably priced.