Dismal service from CMH Nissan Hillcrest

I'm afraid I've had a dismal experience trying to buy a used vehicle from CMH Nissan Hillcrest. I paid for the vehicle in full on 29/06/2019 and still the process has not been completed 3 months later (date of this posting: 25/09/2019). It has become evident that the salesman repeatedly **** to me about various facts and procedures, such as a service the workshop supposedly gave my vehicle and the application of smash & grab to the windows (which I paid extra for). Certain other areas are still murky, to say the least, such as how did my vehicle pass COR with a headlight not working? These are to name a few of the issues that were either not disclosed at all or flagged but not actually attended to. The dealership manager then took over the case but has repeatedly failed to address the issues with the vehicle and clear up all the grey areas. There seems to be very little communication within the dealership and with customers (ie myself). My latest correspondence was a phone call I received two days ago from the manager of the adjacent dealership, to tell me my vehicle was ready for collection, but when I questioned whether the Smash & Grab tinting had been app****, he had no idea and said he would check. He called me back to say that in fact, it had not been app****. So, things are still not looking up.