Hi Job (is that your real name!)?

Had a similar problem a couple of years ago.As i had an account with them, i just took what i believed i was (fairly) owed off of my account balance and settled the rest.Important to do this properly though with 1 recorded del letter BEFORE, giving them the oppertunity to settle amicably,followed by another 14 days later stating what you intend to do.If no satisfactory outcome,then do as above and close your account.
This worked for me,although to be fair, i believe the problem was with one particular aggressive and ignorant manager.

When ECP took over my local factors as part of their global domination plan,my account with them was transferred over to ECP no problem.
(maybe until the next warranty claim?)(

Regards
Colin.