Fears over the safety of personal financial information held by call centres has prompted six million people a year to move their business elsewhere.
Banks, phone companies and retailers are the big losers due to customer concerns over the levels of security used in their call centres.
The findings are from a survey commissioned by business communications company Avaya and contact centre specialist Sabio.
Of 2,000 people surveyed, in January this year, almost half (46%) suspected high level breaches of security at financial institutions; followed by 40% at mobile phone companies; and 37% at retailers.
In financial terms the cost to businesses involved of the six million people, which is equal to 10% of the UK's population, switching their business is an estimated £633m a year.
However, despite the security concerns customers are also annoyed by what they see as overly complicated security.
The survey also revealed more than half (51%) were put off using a provider if there were too many passwords and security details needed.
As a result Simon Culmer managing director UK for Avaya, said: "Consumers' contradictory attitudes leaves businesses stuck between a rock and a hard place.
"By focussing on the three S approach of service, speed and security - brands can improve customer lifetime value, strengthen security and increase brand loyalty."
Kenneth Hitchen founding director Sabio added: "Businesses need to build back confidence in traditional transactions methods.
"Customer service technology can help them achieve this, whether creating confidence in the secure nature of their own contact centre organisations or encouraging the merchants that depend on their transaction services to do the same."