Tracker make it impossible to cancel Subscription

I have been trying to connect to Tracker via all platforms available to cancel my subscription. I took a new car insurance policy in Feb which includes a an in-house tracker service. Using their app, you can send messages for most other functions... the cancel subscription options gives me an error every time. Yet I can send a query on any of the other options. You cannot get any response from them, and I have held on to their call centre without speaking to a consultant!! Yes I have been a customer for many, many years... but cancelling is my choice, and should be just as easy as receiving a new service!!