New figures have shown that those who have been sold Payment Protection Insurance (PPI) along with credit cards or loans and have a complaint are refunded in nine out of ten cases.

The figures, released by the Financial Ombudsman Service (FOS), show that the cases are almost always ruled in the consumers favour when a complaint is lodged after purchasing the controversial insurance plan.

PPI was often offered alongside taking out a new loan or credit card in order to protect against the inability to repay due to redundancy or illness. However, most providers failed to outline the limitations of the insurance such as those who were employed part-time or were self employed were not able to claim. Likewise those working on contracts were not covered.

The figures indicate that banks and credit card lenders are failing to deal with customer complaints effectively.

In the second half of 2008 the Financial Services Authority (FSA) reported a sharp incline in customer complaints to their bank, building society or credit card provider. However, 67 per cent of these complaints were rejected by the provider.

Customers who took their complaints further to the FOS were more likely to have cases ruled in their favour. In sixty per cent of cases regarding investment and insurance companies, banks, credit card providers and direct loan companies cases were ruled in the customers favour.

For PPI cases this figure increased to 89 per cent leading to many consumers receiving a refund.

The FOS has also published the names of the five firms who have received the most complaints; Lloyds TSB, Barclays the Royal Bank of Scotland, Abbey; including Abbey National and Alliance & Leicester and also HSBC. Together they accounted for more than 38,000 complaints in the first half of 2009.

By doing so the FOS hopes to force the high street banks to deal with their customer complaints more effectively.