Vehicle does not belong to me.

I live in George, Western Cape and on a regular basis receive sms that legal action will be taken due to unpaid e-toll fees and fines. I have no idea how my ID number got linked to a GP vehicle. When they send me info it's of a car that does not match one of my vehicles registered under my name. I am so fed up with this harassment. What do I have to do to make you understand that the vehicle under question is not mine and that I might be a victim of identity *****.