Secure drive fedility

This company refuses to terminate contracts after they have run their duration. I have been receiving threats of legal action for an account I paid religiously for 36 months. At the end of the contract, I sent emails to inform them that I would be renewing the contract. I was sent from pillar to post and told that I needed to fill out cancelation forms, I kept requesting for the forms, they eventually sent them almost a year late, I was then told that the account is in arrears, but how? These companies want to keep customers trapped in these contracts. They did not even fit a new tracking device into my vehicle and battery life of these devices only lasts for 36 months, what then am I being billed for? Secure drive, your company is a ****mer! I'm not happy, I would rate you zero!