Bad Service - I still have no car registration papers two months post a cash car purchase

I bought a car cash back in Nov 2022 at WeBuyCars Silver Lakes and to date I am still waiting for NaTis documents. I was told at sale stage that it takes 21 days to get the Natis documents. I have emailed the sales agent to follow up on NaTis documents at least two times and he does not respond to my emails. I have phoned the call Centre a number of times and I have been talking to various agents who do not provide to me clear reasons as to why there is a delay in sourcing my NaTis papers or give me clear timelines on when this matter will be resolved.