Netstar/Oakhurst Insurance Company - Awful Customer Service

I took out insurance on my vehicle through Oakhurst in April/May 2014, and with the insurance was a stipulated necessary installment of a Netstar vehicle tracker. I have never had ANY dealings with Netstar directly whatsoever, either for the installation, an upgrade that happened a year or two down the line, nor for any debit orders. All communication AND debit orders were done through Oakhurst Insurance Company. I cancelled my insurance with Oakhurst in March 2019 and therefore the Netstar should also have been cancelled. My vehicle is, and NEVER HAS BEEN, a high risk vehicle and as such there was NEVER any need for a vehicle tracker in the first place. If these two products are/were linked to each other, then with cancellation of the one product, cancellation of the other product should also happen. I have NEVER requested Netstar to be installed in my vehicle, have never arranged any upgrades with them and have never had any dealings with them - all and any dealings were ONLY EVER done through Oakhurst Insurance and therefore cancellation of Netstar should ALSO happen through them.