Barclaycard and other card issuers will repay the money spent using their card and try to recover it themselves.
The issue became relevant to scores of would-be holidaymakers this week when Flights R Us, a London bucketshop, suddenly went out of business.
Among those who stand to lose all their money is one woman who paid nearly pounds 1,200 by cheque for two flights to the United States.
But there may be other dangers in using a cut-price travel agent, even if payment is made by credit card, as Adrian and Jackie Rorsner discovered.
The couple found their flights to Spain had mysteriously become pounds 20 more expensive between making the booking over the phone and receiving confirmation of the credit card order a few days later.
Mr Rorsner, a pharmacist living in Finchley, north London, said: 'A few weeks ago, Jackie was booking tickets for both of us to Malaga. She called one shop and was quoted pounds 169 per ticket.
'She ordered two tickets and paid for them by credit card over the phone.
'A few days later, we received an invoice for pounds 179 each. All our protests, to the shop itself and to the carrier, have had no success.
'Because there is no record of the conversation between Jackie and the person we bought the tickets from, it is our word against theirs and we cannot do anything about it.'
At least the Rorsners have been stung relatively lightly. For another north London couple, Phil and Helen de Woolfe, the experience was both more costly and disruptive.
Mrs de Woolfe, who restores houses, said: 'We booked a couple of tickets to Turkey for pounds 160 from a bucketshop.
'We thought we had the tickets for a certain day, but when we later checked with the company we were told there were no cheap flights available on the plane that day.
'We were eventually forced to travel on a stand-by ticket on a different day with the same firm.
'As both Phil and I are self-employed, it did not matter so much that we were inconvenienced. But for anyone else who has to take a holiday within a certain period, it could have been a disaster.
'I have learnt my lesson. I never give my credit card number on the phone when I am ordering something. I prefer to go to the shop and pick up the ticket and pay for it there and then.'
A Barclaycard spokeswoman said: 'If a customer complains to us about a case like this we will conduct an immediate investigation into what happened and try to resolve it.
'It is quite difficult in cases where it is one person's word against yours, but sometimes an investigation may show that more than one complaint has been made against a particular shop.
'Apart from paying for a ticket in person, it always makes sense to go to a shop or operator that you, your family or friends have dealt with before. The other point is that customers should always ask for a quote in writing or by fax, so they do have evidence of the price they were first given.'
A spokesman for the Association of British Travel Agents said: 'It is very much your word against someone else's for payments of under pounds 100 on a Visa or Mastercard credit card.'
On amounts over pounds 100, the Consumer Credit Act afforded some protection, he said. The consumer should write to the credit card company to be reimbursed. Then it was up to the credit card company and the travel company to sort out the issue.
'We advise customers to note down the first name and surname of the clerk who takes the booking, the agreed cost, the time of the call, and also to get a receipt as soon as the booking has taken place.'Reuse content