Complaints about banks have reached a ten-year high due to concerns about current accounts, credit cards and scams.
Consumers made more than 80,137 complaints to the Financial Ombudsman Service during the year to 5 April, up 29 per cent on the previous year.
Poor customer service and administrative problems remain key issues for savers, the FOS said.
The free service, created to resolve disputes between consumers and financial companies, forced banks to defend 37 percent of cases in favor of customers.
Current accounts were the most complained about product, with more than 30,675 cases brought before the financial claims arbitrator, more than 4,500 more than in the 2022/23 financial year.
Coutts, a subsidiary of NatWest, came under fire last year after closing the account of Reform UK leader Nigel Farage over his political views.
High Street giants Barclays, HSBC and Lloyds have faced criticism from industry regulator the Financial Conduct Authority after failing to pass on interest rates to savers.
Meanwhile, 24,402 credit card customers raised the alarm with the FOS, with more than half criticising banks for unaffordable or irresponsible lending.
This represents an increase of 265 percent compared to the previous year, when only 3,723 complaints related to this issue were filed.
Coutts, a subsidiary of NatWest, came under fire last year after closing the account of Reform UK leader Nigel Farage over his political views.
High Street giants Barclays, HSBC and Lloyds have faced criticism from industry regulator the Financial Conduct Authority after failing to pass on interest rates to savers.
And banks have also been shamed for failing to protect customers from fraudsters, despite complaints rising by a fifth to an all-time high of 27,312.
About half of these cases were authorized automatic payment scams, where someone is tricked into sending money online to a scammer pretending to be a genuine beneficiary.
In total, fraudsters stole almost £1.2bn last year, including £459.7m in PPP fraud, according to industry body UK Finance.
FOS chief executive Abby Thomas called the significant rise in cases “worrying.”
“It is imperative that all businesses treat their customers fairly and in a timely manner,” he said.
“If consumers feel they have not been treated fairly, they should contact our free, independent service.”
