Customers of the UK's biggest companies often feel undervalued and ripped-off, a survey suggests.
CBI boss Digby Jones says firms must change or lose money
Business consultants RSM Robson Rhodes interviewed high-level executives and clients.
They concluded efficiency drives and subsequent poor service could be costing top companies £20bn.
The Confederation of British Industry (CBI) has urged businesses to take heed and boost profits by listening to their customers' demands.
Researchers interviewed bosses at 25 blue-chip UK companies, including British Airways, Marks & Spencer, BT, HSBC, Woolworths and Easyjet.
They included 16 FTSE-100 companies.
Interviews were also commissioned with 450 randomly selected customers.
The report states companies often lose touch with clients' wishes as they grow and either cut popular services or keep those which are not wanted.
On top of that, it says cost-cutting measures that lead to slow telephone response times and customers being passed around call centres could end up costing firms in the FTSE 100 £20bn.
Customers were also unhappy with the quality of service they receive for the price they pay.
Of those quizzed, 80% felt companies were not meeting their expectations while 83% felt senior managers were not "customer focused".
CBI director general Digby Jones said: "This is a pioneering report that highlights the critical issue of mis-servicing.
"We welcome the research and urge CEOs and senior executives to consider the report's main theme, that companies have focused too much on efficiency at the expense of their customers."
Eric Benedict, a partner at RSM Robson Rhodes, said:
"Many CEOs have not yet grasped the urgent need to better align their business strategies to the needs of their customers.
"If they get this right they have a great opportunity to enhance their bottom lines."