I used to work, on a self-employed commission only basis, for a firm which claimed that it could get traders' business rates down. The firm based its claims upon the fact that some business premises had been wrongly assessed and successful challenges had been made to their rateable values. They always omitted to mention that were only a small minority of business where people had got their rates reduced. (They also led people to believe that all of the successful challenges mentioned in their literature came about through their services. In fact, most were through rival companies or the result of direct appeals by business owners).
The firm charged an up-front fee, which it deducted from the 25% cut it took from any rebate obtained. They promised that they'd return the up-front fees if they couldn't get the rates down. (Is this starting to sound familiar?).
A short while after I ceased working for them the firm went bust, taking all their clients' deposits with them. So, having read that, do you really feel happy about parting with nearly �500?
If you're in a position to reclaim money from your credit card lenders, you can do it yourself. See here:
http://www.thisismoney.co.uk/reclaim-credit-ca rd-charges
and here:
http://www.moneysavingexpert.com/reclaim/credi t-card-charges
Chris