Ian,
MyChargeBack has handled cases from thousands of clients in more than 150 countries working opposite more than 750 banks. We would be more than willing to put you in contact with one of our former clients who lives near you so you could ask for a reference. Without knowing what the particulars of your case are, what we can promise in 100% effort to recover your funds. We cannot promise 100% success, since all cases are different -- different payment platforms, different banks, different merchants who work with different banks themselves, different payment dates -- all of which impact a client's chances of success. Before accepting any case we provide the potential client with a free initial consultation, during which time we evaluate together what those chances are and let you decide. As a matter of policy, we do not accept case that we judge beforehand to be unwinnable.