BBC News website disability affairs reporter
Research shows that issuers of the new chip and pin cards are failing to tell visually impaired customers, who are unable to use keypads, that there is an alternative.
Organisations that issue cards should be offering anyone whose disabilities make using a keypad difficult the alternative of continuing to use a signature card.
Using a keypad won't suit everyone
But a second mystery shopping exercise carried out by the Royal National Institute of the Blind (RNIB) showed that only one in five bank branches provided the correct information, while just under half of the call centres contacted told people about the alternative arrangements.
The RNIB contacted 14 organisations and made 5 calls to each call centre and visited bank branches on five separate occasions.
When the organisation conducted a similar exercise six months ago, it asked banks and building societies to address the issue by providing appropriate training for staff.
It said that it would 'name and shame' the worst offenders if things failed to improve.
It describes its latest findings as "shocking".
"We would have been the first to congratulate card issuers who got it right - but none have," said RNIB head of policy, Steve Winyard.
The organisation representing the card issuers says the RNIB has highlighted a communications issue which it takes "very seriously".
Chip and Pin points out that there are more than a quarter of a million call centre and bank branch staff in the UK, and that training them all to respond correctly on every occasion is a significant undertaking.
"We will keep working on this until everyone gets the right answers to their questions," a spokesperson said.
American Express and Alliance & Leicester scored worst in the survey.
An Alliance & Leicester employee told a caller that there was no alternative to using a chip and pin card.
From January retailers will bear the risk of fraudulent card use
Responding to the RNIB's findings, Alliance & Leicester described the bank's poor rating as "disappointing".
In a statement the company said it would be encouraging customers to try chip and pin before they opt out.
"When pin is unsuitable, because of disability, we are happy to issue chip and signature cards on request - so far we have issued 738 of them."
A caller to American Express was told: "Blind people should be able to use keypads because they're able to use telephones".
American Express says it has been training its customer service staff on this issue for some time.
But it says it is not currently issuing any chip and pin cards to its UK customers.
"We are extremely sorry that due to human error, the customer service representative did not provide the correct answer," a company spokesperson said.
"We are reviewing training to ensure that this doesn't happen again."
The RNIB survey did produce some positive results, although none of the institutions contacted scored 100 percent.
Barclaycard, Cheltenham and Gloucester, Co-op Bank, Lloyds TSB, Natwest and Royal Bank of Scotland all scored quite highly.
From January 2005 the liability for the fraudulent use of debit and credit cards will shift from the company issuing the card to individual retailers.
This means that unless a person's card has been specifically programmed to be used with a signature instead of a pin, retailers are likely to insist that the customer uses a keypad.
In the case of chip and signature cards, liability for fraudulent transactions will remain with the card issuer.
Although concern has been expressed for customers with visual impairments, difficulties with manual dexterity and those who find it difficult to memorise numbers, not everyone in the disabled community thinks the technology will be problematic.
A subscriber to E-Access Bulletin - an email newsletter for visually impaired people - recently wrote to ask what all the fuss was about.
"I use a French credit card, and when I type in my pin number the only problem I sometimes have is knowing where the 'validate' button is," wrote Clare Page from France.