Voluntary termination of a pcp agreement.

[Marco11]

Hi everyone, I know this topic has been covered before but....I have recently Voluntarily terminated a pcp agreement on a car with black horse finance. I did this in writing in accordance with section 99 of the consumer credit act 1974. Approximately one week later I received a response from black horse acknowledging my VT letter but there was also a form to fill out to confirm the voluntary termination, I filled this in out of courtesy but I did not sign the form because a section of it was to accept liability for any damage etc to the car. The car was in great condition with full service history and well below the agreed mileage. Black horse have now returned this form saying that 'if I don't sign the form then they will not accept the voluntary termination'. I have already dropped the car off at the auction and no checks were carried out on the car regarding condition etc I simply handed the keys over with the log book and service record etc. I have taken lots of date stamped pictures of the car and relevant documents etc. Please correct me if I'm wrong but I'm under the impression that by me writing a letter to terminate the agreement that I don't have to sign anything from the finance company? And how do I respond to the return of this form? Thank you in advance for any advice it's very much appreciated!