device not working

I took a car tracker contract with Netstar on September the car was not arming on the app ,then October I called Samkelisiwe Ndebele regarding the panic button that I suspected was also not working and the app she advised I press the panic button which I did and confirmed it was not working as I never got the SMS she said I will get since then I’ve been requesting help with no luck I’ve been sending email and calling but no one is helping ,I called again the 12 November spoke to the supervisor that advised he will investigate the matter ang get back to me within 54 hours or less but never got back to me and I’ve been requesting a cancellation letter which to date I didn’t get .i called again the lady said to be supervisor just kept quiet. Further, I was involved in a crush and there was no detection by the unit as advised on the contract. All in all, the device isn’t doing what it is supposed to do as per the contact and call when I was taking the contact. I therefore request help to cancel this contact as the company Netstar defaulted in the contract and with being liable for any settlement or cancellation amount.