NatWest customers have been left unable to see their money after a technical fault hit the bank's mobile app.
The issue, linked to its recently introduced savings "pots" feature, affected hundreds of users over the weekend and into the start of this week.
Customers reported problems when trying to move money in and out of the digital pots through both the app and online banking, with some saying their funds appeared to disappear.
The pots feature, launched earlier this year, enables account holders to ring-fence portions of their current account balance for specific purposes such as savings or bill payments.
One customer who opened a pot over the weekend described being left significantly out of pocket after attempting to withdraw funds.
"I transferred £3,500.00 back out of the pot into my account to pay for an Airbnb and the money has disappeared," he told The Sun.
After contacting the bank, he was informed there was a problem with the pots system but staff could not explain where his funds had gone or when they would be returned.
"They can see that the transaction has been posted, but did not know where my money was," he said, adding: "I'm now £3,500.00 overdrawn and have no idea where my money is."
Customers reported problems when trying to move money in
| GETTYNatWest has confirmed the technical issue has now been resolved and affected customers should see their account balances corrected by Tuesday afternoon.
The bank stated that no customers were ultimately left out of pocket as a result of the fault.
A spokesperson said: "Some customers have experienced a delay when withdrawing or topping-up their Pots through our mobile app and online banking.
NatWest has confirmed the technical issue has now been resolved
| GETTY"We've resolved this and are applying these transactions to customers' accounts, so they will see their balances update shortly. We're sorry for any inconvenience caused."
The bank also confirmed the problem was confined to NatWest accounts only, with customers of its sister brands Royal Bank of Scotland and Ulster Bank unaffected.
Juts last month almost half a million Lloyds, Halifax and Bank of Scotland customers saw other people's transactions or had their own data shared in a recent IT issue, the bank has revealed.
Lloyds Banking Group had not said how many customers were impacted by its glitch on 12 March, which left some people "panicked" after seeing payments, charges and national insurance numbers belonging to others in their apps.
WorThe bank also confirmed the problem was confined to NatWest accounts only
| GETTYBut in a letter responding to the Treasury Select Committee's enquiries about the incident published on Friday, Lloyds said it had affected up to 447,936 customers.
Committee chair Dame Meg Hillier said it reflected modern banking's trade-off in enabling convenience but also "unpredictable errors".
"Modern banking methods mean we can now perform a variety of tasks on our phones in a matter of seconds, and almost anywhere," said Dame Meg.
"What this incident brings into focus is the fact that there is a trade-off."