Fees and charges triggered by mis-sold PPI premiums should be paid back, the Financial Ombudsman Service said after a BBC investigation claimed customers could have possibly been under-compensated by £1 billion.
Principal Ombudsman Caroline Wayman said: "If a fee is the result of the mis-sold PPI it should be given back, and if it's not included that would be a mistake."
She also recommended that credit card customers who fear their fees and charges were left out of compensation calculations approach their banks to discover what happened.
Victims of the payment protection insurance mis-selling scandal could have potentially been under-compensated by an estimated £1 billion, a BBC News investigation has found.
Customers who may possibly have been affected had PPI on credit cards issued by Lloyds Banking Group, Barclays, MBNA and Capital One, the BBC said. All these banks claim to make every effort to pay the correct amount of compensation.
The estimated shortfall uncovered by the BBC arose because some fees and charges that were triggered by mis-sold PPI policies have been left out of compensation calculations, which also involve adding interest, thereby dramatically reducing the amounts some customers would have otherwise received.
Claims management companies should be banned from making "nuisance calls" about mis-sold PPI, after it emerged they had probably pocketed £5bn from compensation claims.
Citizens Advice Bureu (CAB) chief executive, Gillian Guy, explained:
By banks originally dragging their feet and providing inadequate redress, claims management companies seized an opportunity to take up to 25% of people's compensation for admin work that consumers can do themselves for free.
Some claims management companies operate well below the standards that are expected and sometimes outside of the rules.
The regulator needs to quickly revoke the licences of firms that are not up to scratch.
We'd like to see a ban on cold calling by claims companies which would spare people from nuisance calls and protect consumers from predatory firms.
Some 28% of claimants who pursued PPI compensation felt under pressure by their representatives to do so, research has found.
Consumer research carried out by The Citizens Advice Bureau (CAB) found almost a third of those who used claim management firms to pursue their compensation felt under pressure to continue with their claim.
This came after claims management firms were estimated to have made £5bn off consumer claims for the mis-sold insurance since the compensation drive began.
CAB also found a lack of understanding among consumers about how best to claim compensation.
Nearly two-fifths (39%) of people who had used a claim firm said they were not aware they could have made the claim themselves, according to a survey of more than 5,000 Britons.
It is not over - the biggest consumer scandal continues to cost more and more for the banks.
Lloyds have revealed this morning that they are paying out another £750 million in compensation which doesn't just push them into a loss, when their books are looking better, but takes just their bill for the mess to over £8 billion.
That is a staggering amount of money - and a reminder that mistakes from years ago continue to hamper the banks' full recovery.
Complaints about financial firms have surged to a record high as a huge insurance mis-selling scandal continues to weigh on the industry.
The Financial Ombudsman Service (FOS), which settles disputes between consumers and financial firms, said new complaints rose 15% to 327,035 between January and June on the prior six months.
That was driven by a 26% hike in complaints about payment protection insurance (PPI), where people were charged for loan insurance which they did not need or could not claim on.
The ombudsman said some lenders continue to drag their heels on repaying mis-sold PPI, causing "long waits and unnecessary delays" for customers.
The consumer group Which? said the Government must give regulators more powers to crack down on "unscrupulous claims firms" that contact consumers about mis-sold PPI claims "without permission."
Richard Lloyd, executive director at Which? said, "Consumers can register their frustration with nuisance calls by using our new complaints tool which will send a clear message that more needs to be done to stop this menace."
Mr Lloyd's comments came as the Citizens Advice Bureau said more than 30 million people have received unwanted messages about claiming for mis-sold PPI.
The Citizens Advice Bureau wants cold calls about the mis-selling of Payment Protection Insurance (PPI) to be banned and said it is "completely unacceptable" for calls to disrupt family time and work meetings.
Over a third of the complaints Citizens Advice handles about financial services stem from a cold call.
There is a particular problem with claims management companies. People are finding that sometimes the promises made over an unexpected phone call aren't delivered.
This means people who have been mis-sold PPI lose out twice: first at the hands of the bank and secondly from the claims firms because they don't get the full compensation they deserve. I want financial services firms to be banned from cold calling.
According to the Citizens Advice Bureau of the 30 million people who were disturbed by an unwanted cold call about mis-sold Payment Protection Insurance (PPI):
- One-in-four people (27%) received their most recent call during a family meal, while around one-in-seven (14%) received the call at work, including during meetings and presentations.
- Approximately one-in-eight (13%) were disturbed while enjoying a film or watching TV.
- Texts to mobiles, telephone calls and automate messages were the three most common ways in which people were contacted about PPI claims.
- Citizens Advice research found 56% of complaints about PPI claims management stemmed from cold calls.
More than 30 million people have received unwanted messages about claiming for mis-sold Payment Protection Insurance (PPI), according to figures released by the Citizens Advice Bureau.
Two-thirds of British adults, equivalent to 32 million people, said they have received an unwanted telephone call, text, email or letter about PPI, the figures show.
Of these, 98% did not feel that they had given their permission to be contacted in this way, and 55% estimate that they were contacted more than 10 times in the past 12 months.