Norman Bisset Group harassment

I keep on getting phone calls from this company. The collection agents are very rude and keep on threatening me for a Cartrack account that I don't have and never had. I have never done business with Cartrack and even when I ask for the vehicle in which this unit must be in they can not answer me. I have requested they please find out and apparently it is not their responsibility??? I have blocked the calls on my phone an now receiving sms'es with letters of demand on which they do hot even have the correct spelling of my name. This has been going on for over a year. If this continues any longer I will not have a choice but to give this to my legal representative to sort out and I will also ask for a cost order against them from the court. I am really fed up of this harassment. If you want to collect "debt" from me please make sure that I did or do have such an account and I am sure that if I did have an account I would have filled in my credentials correctly. It is a disgrace that they treat people this way.