IMPOSSIBLE TO CANCEL NETSTAR

IMPOSSIBLE to cancel Netstar. I have sold a vehicle that for which I had a subscription with Netstar since 2019. HOWEVER, for some reason NETSTAR insists that I have only signed up from October 2020. And apparantly I have signed a contract for 36 months. I have NO SUCH CONTRACT in my possession, and the "customer services lady" is not able to send me such a copy. Neither is she able to furnish me with the contracts department's contact details. I am in "arrears", I have to pay a penalty cancellation fee. NO ONE from NETSTAR communicates/responds via email. A 1-star rating is too good for this pathetic company.