The Funding Corporation - Advice /help required

Stevemann55

In 2004 I purchased a car with car finance from the Funding Corporation. In March 2006 I lost my job and the car was re-possessed and sold at auction leaving a balance of approx £10k which the Funding Corporation subsequently took me to court for and a CCJ was issued against me and the funding Corporation also secured a restriction against my property. I agreed a payment plan with the Funding Corporation with low but affordable monthly payments which has meant that it has taken until now for me to be in a position to finally settle the account, or so I thought. In February I asked for a balance as I had not received a statement for a very long time (but I was keeping my own records so I had an idea of what was still outstanding) and the statement was received by return. I paid the balance on the statement and having now finally settled the account, I contacted the Funding Corporation to request that the restriction against me was now removed. It has taken from February until now to obtain a response from them despite chasing weekly by email and the response has staggered me. The Funding Corporation have advised that they have been accruing interest of 20.7% per annum against the outstanding balance which they have never discussed with me or made me aware of and that I staggeringly owe them £28,566.73 in interest charges. 

I am now at a loss as to what to do, It has taken me a very long time to get this debt paid off only to find out that I am now being told I owe 3 times more than I owed in the first place and they will probably be accruing interest against this amount now which means it will be impossible for me to pay it off.

Does anyone have any similar experiences or can advise me of any rights I might have or actions I can take as I don't know what to do.