Overpayment recovery rate appeals

Hi,

is it possible to appeal the rate at which an overpayment is being recovered?  If so, does anyone have any experience of this?

My customer is a pensioner, she was convicted of fraud in 2010 and has been paying the overpayment back at the minimum rate on grounds of hardship.  The rate has been increased to the fraud rate £17.75.  The customer provided a detailed list of her income and expenditure which shows her expenditure exceeds her income and that she is suffering severe financial hardship.  However, they LA still refused to reduce it as they are only considering certain percentages of expenditure and state that customer has excess income after their clauclation.

Thanks

Allan