Car sold 8 months ago yet car still on my name and receiving fines and toll gate accounts

I sold my car to this garage on 04 January 2019, went to them four times to ask why the car is not de-registered off my name. Today is 20 August 2019, again I went to the traffic department and they told me the vehicle is still on my name, I am thinking the garage will probably keep the car licence until its expiration in November. Three months ago I spoke to the owner of the garage, he promised to resolve the matter, but I have never been contacted since then. I get speed fines and tollgates accounts on monthly basis. If you want to avoid this kind of problem don’t deal with them. UTTER DISGUSTING SERVICE