I Bought a Land Rover Discovery4 with a Dekra Gold rating from We Buy Cars Dome on Friday the 25 Oct 2024 and on Monday 28 Oct 2024 the car would not idle when starting it

I Bought a Land Rover Discovery4 with a Dekra Gold rating from We Buy Cars Dome on Friday the 25 Oct 2024 and on Monday 28 Oct 2024 the car would not idle when starting it. I phoned the sales person and they told me to take it to a RMI approved service centre to be checked out, the service centre can't really say what is wrong with the car and on the 1 Nov 2024 the car did the same thing and I contacted We Buy Cars again but they dont realy help, keep saying I must take it to a RMI service centre. Not happy with the after sale service and the car with a Gold Dekra Rating that only drives for 3 days then it brakes down.