I tried to get a mortgage but was turned down by the underwriters as there was an issue of a late payment on my credit card back in 2012. After getting copies of bank statements I found that all payments were made by standing order each month, I then wrote to the company who told me that the account was marked as satisfied but the default would last XXXX years.i have now written back to them saying I am not happy with the result as I feel I have been unfairly penalised. I am XXXX years of age and am having difficulty getting a mortgage because of the years left ( XXXX ) max for mortgage.i am renting a property which is costing me XXXX more than the mortgage would have cost me, and gone through lots of stress because of this. 
The rest of my credit report is all up to date and in order apart from this, I work in retail banking so I know how important it is to always keep payments in order. I would be grateful to know your views on my situationThank you