Firstly, do not send them anything, you don't have to.
Second, do not speak to them on the phone ever, and insist on all future communication in writing.
Third, never sign anything you send, just type your name.
OK, so thats the beginning.
The next thing is to have a good read about CCA requests. The real basics are that a consumer credit act agreement is the form that needs to be signed when credit (most credit) is taken. If this is not done correctly, you are in a very strong position.
There are many threads on the subject, the forum is here
http://www.consumeractiongroup.co.uk...bt-collection/
and have a very good read of this
http://www.consumeractiongroup.co.uk...le-useful.html
it really will help to look at peoples threads and experiences. I know it's a lot of reading, but if you can spare the time it will pay dividends in the end.
There will be lots of help, but it would be invaluable if you get a good understanding yourself of whats involved.
It's a lot to take in in one go, but good luck with it.
louis