What is an unaffordable Doorstep Loan?

The Financial Regulators explains that a loan is unaffordable if you could not make the repayments without borrowing again. This could be borrowing from the same lender orfrom someone else, while getting deeper into your overdraft or ending up being unable to pay a "priority bill" such as a utility bill or rent.

Even if you have always paid your Provident/Morses Club or other door step loan on time, it could still have been unaffordable.

If the lender had realised the loan was unaffordable, they should not have given it to you.  Where this is the case you are entitled to a refund of the interest you paid.