Accounts department unwilling to resolve account

I have had an account with Chubb for the last couple of years. In 2012 I had my alarm system upgraded by Chubb at a huge expensive. Due to dishonesty on the part of Chubb I have battled for the last couple of years to have an amount removed from my account. As a last straw I stopped paying Chubb for their services until the account was resolved. In October I sent an email as cancellation of Chubb services and requested account settlement. Only to be told I had to pay an astronomical amount for services which they continue to bill me for. I am at my wits end with Chubb Cape Town. The arrogance is infuriating and I am about to hand this over to legal for them to fight it out. Please resolve this before I take legal action. I have all the email proof and contact details to cover my end.