Netstar not responding to phone calls, emails and WhatsApp for cancellations

When I try calling the phone lines for the option of cancellation, I do not go through. I hold on the line for over 15 minutes with no consultant attending to my call. Furthermore, I have written an email as well go through the WhatsApp line requesting cancellation and there is no response from Netstar. The only time I hear from Netstar is when increases are involved and this is worrying me. I urgently need to cancel Netstar because the new vehicle I have came fitted with a tracking device from another company.