Hundreds of customers say they are still unable to access their savings accounts with NS&I due to its new online login system, three weeks after the issue was first reported.
They have taken to the national savings bank's page on consumer reviews website TrustPilot, to complain that they cannot log in after it implemented a two-factor security system.
This is Money has also heard directly from readers who have been affected by the ongoing technical issues, and say they are unable to log into their accounts via the website.
Tech trouble: NS&I customers say they have been left with no way to access their savings after the two-factor authentication system has complicated the log in process
One customer, Peter, emailed This is Money after a month of failed attempts to access his account. Every time he tries to log on online, he says, the system produces a message saying there has been a technical issue and to start again.
Despite repeated calls and emails to NS&I's help team as well as lodging a formal complaint, he says he is yet to hear back.
He is not alone. Nearly every day for weeks, new complaints have appeared on NS&I's public page on consumer website TrustPilot from customers who are frustrated and unable to access their savings.
Many on the site report that the NS&I security system says that they have reached their 'trusted device limit' when they try to log in - meaning that they have reached the maximum number of different devices they can use to access their account.
However, many users say that they receive this message despite attempting to log into the site using the same device, for example a home laptop, they have always used and without attempting to log on from anywhere else.
In August This is Money reported issues with the two-factor login system. At the time NS&I's social media team was responding to complaints reassuring customers that the problem with its systems and phone line were being fixed.
Yet nearly three weeks later the login system appears to still be blighted with issues.
'The vast majority of people have been able to complete the process successfully.'
It added that anyone who needed support should contact its helpline on 08085 007 007, which is open from 7am - 10pm every day.
The team suggested that customers who get the message saying they have exceeded the number of trusted browsers should make sure they are not browsing privately, by using the web in 'incognito mode' as this may be the source of the issue.
In addition, they also advised customers experiencing problems to take a look at their FAQ page or use the web chat function on the NS&I website to talk to a member of their team.
One customer who goes by R Willis on TrustPilot said he had success accessing the site through web browser Opera, after two days of trying through Chrome, Bing or Edge with no success.
Others however say they are ready to leave NS&I all together as a result of their recent experience.
Steve posted on Trust Pilot to say that after both being unable to access his premium bonds and bad customer service, he and his wife will both be closing their accounts, adding 'Life is too short to deal with NS&I!'
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