Discovery Insure/cartrack and communication problem

My car insured with Discovery. Cartrack fitted but has testing fault. Consultants phoned 6 times, each time "call ended" in middle of conversation. No attempt by consultant to ring back when this happens. E mail requesting advice, ref number supp**** - still awaiting feedback/advice. Useless comms- poor customer service. Vehicle not secure with faulty cartrack faulty.