Holding me to a contract I knew nothing about

I took up a Netstar tracking device in August 2023 as advised by my insurer at the time MiWay. I have now recently moved insurers and understandably no longer require the tracking device. I contacted Netstar 2 weeks ago to cancel my debit order but was advised that I apparently signed a 36 month contract with them. I informed them I did not sign any hardcopy. They informed me they will listen to the call recording. Up to now, no feedback. I followed up with the this morning and was informed that no request was logged. This is great Service. I need urgent feedback as I would like to understand since when do you take up a contract that ties you down? What if I traded the car in, am I still bounded by the contract? This does not make sense and Netstar cannot hold me to a contract.