Royal Bank of Scotland Group Plc said it has processed the 600,000 credit- and direct-debit transactions that were delayed this week in the government-owned bank's latest payments failure.

"The issues customers were experiencing in relation to delayed credits and debits have now been resolved and accounts have been updated," the bank said in a statement today. "We are extremely sorry for the inconvenience and distress that this has caused our customers."

The bank was criticized by lawmakers and had to contact the U.K.'s Financial Conduct Authority on Wednesday after hundreds of thousands of transfers went missing. The computer system failure came just seven months after the Edinburgh-based lender was fined 56 million pounds ($89 million) for a 2012 computer collapse, which left millions of people without access to their accounts for weeks.

RBS originally said the problems would be fixed by Saturday. Andrew Tyrie, a Conservative lawmaker and chairman of the U.K.'s Treasury Select Committee, said June 17 it was "unacceptable" for customers to be out of pocket for that long.

"If any customers are still experiencing issues please contact our call centers or come into a branch where are our staff are ready to help," the bank said. "We will continue our work to make sure that no customer will be left out of pocket as a result of this issue."

RBS is spending 150 million pounds a year to improve the resilience of its computer systems and investing in new technology, Chief Administrative Officer Simon McNamara said on Thursday.

McNamara could not guarantee there wouldn't be another RBS computer failure in the future, saying "this is technology, it is complex and it will fail."

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