RBS bosses have refused to reconsider controversial branch closures despite widespread cross-party criticism.
MPs on Westminster's Scottish Affairs Committee said the response to the bank's plans to shut 62 of its branches in Scotland was "overwhelmingly negative", with customers - particularly those in rural areas - feeling badly let down.
However Jane Howard, managing director of personal banking, and Les Matheson, chief executive of personal and business banking, insisted RBS was responding to changes in customer behaviour, including a rise in digital banking.
Despite repeated calls from MPs, they would not commit to looking again at the closures.
Concerns have been expressed over the impact on elderly, vulnerable and small business customers, particularly in rural locations, by groups such as Scottish Rural Action.
Committee chairman Pete Wishart said: "I don't think I have ever experienced such an overwhelming negative response to a single issue in my 17 years as a Member of Parliament."
He added: "I think what's also disappointing is your defiant response to this, where you are singularly saying you are refusing to reconsider any of these closures which is going down particularly badly in a number of rural areas."
MPs were told the closures would save the bank around £9.5 million annually, and were not being taken forward to save money.
SNP MP Tommy Sheppard said: "It is the case you could easily afford not to do these closures and take another year to consider the community impact and to consult further."
Labour's Danielle Rowley and Lib Dem MP Christine Jardine pointed out the bank had received a £45 billion taxpayer bailout during the financial crash.
Ms Rowley asked: "Where is the gratitude...as a thank you to our communities?"
Mr Matheson said: "We understand the support that the bank has had and clearly we appreciate that, but again, we have to take account of changes that are happening."
He said less than 1% of RBS customers go into a branch on a weekly basis, with a 42% reduction in branch transactions in Scotland since 2014.
RBS was offering people a greater variety of ways to bank, through post offices, mobile vans and new community bankers, as well as online and in remaining branches, he added.
"We understand that customers are concerned about the change, that customers find change difficult, and we are committed to helping them through that process, and we have lots of ways of doing that," he said.
Ms Howard said: "We are both personally committed, as are all of our colleagues, to helping every individual customer."