Trying to cancel my Beamie tracker

I have been trying to cancel my subscription for the past 3 months with no success, I have sent emails to the email that was provided to me, with no reply. Everytime I phone I can either not get through or they drop the call. Now they are threatening to hand me over after i returned my debit order, I refuse to pay for a service that I no longer want and cannot cancel, due to there internal issues or bad service.