By Lawrence White and Noor Zainab Hussain
(Reuters) - Dozens of customers of Britain's TSB Bank said on Wednesday they still could not access its digital services, after the bank's CEO said earlier its mobile and online banking platforms were up and running following five days of disruption.
TSB, owned by Spain's Banco Sabadell, on Tuesday had said it needed to take its mobile application and online banking down for a "few hours" after working for 48 hours to fix the problems.
"Our mobile banking app and online banking are now up and running. Thank you for your patience and for bearing with us," CEO Paul Pester said on Twitter on Wednesday morning.
But some TSB customers responded on Twitter that their access was still blocked, and that the bank's website as of 0913 GMT said it was "limiting access to internet banking."
The five-day outage is one of the longer-running disruptions to a bank's online platform in recent years, and highlights the risks banks take in moving from so-called legacy computer systems to newly-built platforms.
Customers on Twitter complained they could not access their money online and in some cases in TSB branches, leaving them unable to pay bills.
The outage follows a planned migration over the weekend of TSB's computer systems, as it shifted from the platform of its former owner Lloyds Banking Group to a newly-built system called Proteo developed by Sabadell.
TSB owner Sabadell had initially said the move was a triumph, issuing a statement on Monday on the "successful" completion of the migration according to an archived snapshot of the release on the bank's website seen by Reuters.
The statement has since been removed from the Spanish bank's website.
TSB's use of Lloyds' IT platform has cost the bank hundreds of millions of pounds a year since Sabadell took over TSB in 2015.
Sabadell booked costs of 35 million pounds in the last quarter of 2017 and 45 million pounds in the first quarter of 2018 for the IT deal. When Sabadell first announced its acquisition of TSB in the first quarter of 2015, it said it estimated cost savings of 160 million pounds per year in the long run after completion of the deal and migration of the IT platform.
Royal Bank of Scotland's Irish division also reported an issue that led to salaries going missing from some accounts on Tuesday.
(Reporting by Lawrence White and Noor Zainab Hussain, additional reporting by Jesus Aguado in Madrid. Editing by Sinead Cruise and Jane Merriman)