Lack of notice

I have signed into a 24 month data contract with Telkom receiving a laptop, about 5 years ago and it has come to my attention that I am still paying that contract. Telkom has not ever sent me any notice requesting if I want to cancel or extend my account as all my other service providers has done in the past. I will defnitely be much more vigilant in the future as I have lost a lot of money through their lack of notice and I have also not received any product by them when they extended my contract without my consent. They are however very quick to send accounts when your account is in arrears. I have now sent in a cancellation form to them, but have also not received any response. Not happy client.