I would not have got in contact with the company that have asked you to pay again because as you have now done this you cannot be what isd called 'statute barred' which basically means that as 6 years has passed with no contact you could take them to court for harassment! but as you have now contacted them the best you can do is to work out a figure with them but it is ridiculous after 6 years as I have the same problem at the moment excepting it has been 6 and a half years and no I will not contact them because the minute I do my statute barred goes out of the window and I have to pay because I have contacted them, look at the limitations ast of 1980 which applies to england and wales. Good Luck and let me know how you get on please.