Poor service delivery :'(

I have a tracking unit which was installed for me through my insurance on my Ford Figo last year. I sold the car and I requested that the unit be fitted into my new vehicle but there was about a weeks delay between the de-installation and when I bought my new vehicle (so I had to cancel my insurance). I've been calling several times since the first week of December for this fitment to be done but with no luck. Jason was assigned to my case with reference ********** and i was given his contact number as ********** 00 but he has been unreachable and when i finally talked to him he was unable to help me. I'm now being billed for a tracking unit that is sitting their your offices collecting dust. :'(