Distasteful after-sales service

Worst after-sales service ever endured from Group 1 Hyundai Knysna. I purchased a vehicle in February, they delivered it to me (in Cape Town) till this day I am still driving around with the dealerships CX registration number. Numerous attempts made to have them organize my new plates (as this paid expense also makes part of the whole contract). The sales person who was so nice at the beginning (as they always are when reeling you in) is giving me a new story every time I make contact with him. At one stage he even asked me if I could take the car for roadworthy, this after 2 months I've been driving it. Someone please tell me is this normal??? I am still choosing to withhold the sales person's name as I do not want to dent his reputation. He's still a young lad but he is rather very untruthful. We are now heading to June 2022 and the latest story I heard is that the courier could not find my address, as he told me a week ago that he will courier the plates. (mind you this is the same address that he has been to twice). Group 1 Hyundai Knysna or Group 1 Motors or whatever you guys are now, please do something if you care about your reputation going down for something so stupid!