Not happy with service, just to deactivated one unit and reinstall is hard for netstar

I have called them to inform them of my car being sold and would like to reinstall the tracking unit to my new car, I have been waiting for month now for Netstar to call me, everytime I call they need to find out, or head office must arrange, I'm not happy with your service this time, the consultant won't even call you back after they put the phone down on you, if my car gets ****** after I have been referred to them by my insurance, I will sue this company, service is poor,never had this before