Odometer reading tempering/shaving

I bought a 2018 VW kombi with 137 000km readings on the 26/04/2022 for almost R450 000 and only to discover that it has already been serviced for 183161km in 2019. Now I'm stuck with a car that has +/- 490 000km and they refuse to take it back because they claim that they also bought it as is. I really need help with this because I will not rest untill they solve their mess. And they are pushing the brown envelope to whoever I run to. And funny enough, they joked about not to be exposed in social media if I experience issues with them...