Audi warranty a ****

I bought an audi A3 from Citton Cars in May 2021, the km's were around 60000. So when I bought the car it was still under Audi's 100000kms service plan and warranty. Around November/December the car gave an error ''Fuel pressure low'', we took the car to Audi and they said they fixed the problem but days later it gave the same error and they adviced us to bring the car in January when they will be able to borrow us their inhouse car (This is audi centurion). Then they went on to check the car - First they say this car looks like it was opened up by other mechanics other than audi, then I asked how that is even possible, who would take their car that has a service plan and warranty and take it to where you will pay?. Then I asked for a formal report on the car, they send an invoice for R260 000, yes R260 000 and they said warranty will not cover, now this is their reason. Audi is saying the car gave this warnings and the owner failed to take the car to dealership (By owner they are referring to the previous owner not me). So my question, how is that even my problem? According to Citton cars (who by the way have also said that this is not their problem, we must sort it out with Audi), say that before they sell cars that are still under warranty they take them to their manufacturers to check if all is in order, so my conclusion is that they should have said to Citton at that point in time that the car is no longer under warranty, in turn Citton would have then told us the car is no longer covered under Audi's warranty, which definately woluld have meant that I would not have purchased the car. I am very upset because my husband wanted to purchase a BMW/MERC and I convinced him based on the fact that my friends drive audi's.