Tens of thousands of people were feeling short changed last night after a massive system failure wiped out all the Northern Bank's ATMs.
Throughout the province yesterday, frustrated people found themselves unable to withdraw money from hundreds of machines.
Customers trying to use Northern Bank debit and credit cards also faced misery as their transactions were refused, leaving many embarrassed and unable to make purchases.
The problem - which arose after the Danish- owned institution's central system crashed - affected all of the Northern Bank's 94 branches nationwide, including 25 in the greater Belfast area.
Speaking to the Belfast Telegraph last night, a spokesperson for the bank apologised to customers and blamed a glitch in the ATM network.
"This issue is the result of a technical problem with IBM who support this network," she said.
"We are working closely with IBM to restore service to our customers as soon as possible.
"We apologise unreservedly to any customers who are being affected by this situation."
Last night, the Belfast Telegraph tried to withdraw money from cash points at two of the major branches in the city centre, but found them still 'temporarily out of service'.
The spokesperson, however, stressed that engineers were making every effort to repair the fault and said the network would be up and running again as soon as possible.
"Any customer who urgently needs to withdraw cash can still do so at any Northern Bank branch or can use their chequebook," she added.
Messages outside the Northern Bank's headquartwers in Belfast yesterday alerted customers to the problem.
But it is understood that the system crash went wider than Northern Ireland, also affecting machines in Europe owned by the Northern's parent Danske Bank.
This is the second time in recent months that the Northern Bank has been at the centre of a problem with cash machines.
In February, it emerged that Nationwide customers using Northern cash machines were not having pay-outs debited from their accounts.In that case, however, the error was not linked to Northern Bank technology, but to Nationwide's.