Renault Silverlakes

Today marks an entire month battling with Renault Silverlakes and @Renault_SA about my car I was told that they found a peace of plastic inside the engine but when I asked about where exactly it might have entered from there was no answer given, all I know is I drove my car to Renault Silverlakes and +_30min of picking it up it had an oil leak then after driving it for less than 100KM it broke down around 22:45 the same day I was told my warranty rejected the claim and I have to pay +R26000 to fix the valves which are bend by 0.05mm. car had no issues before it went for service 1. I questioned how did a plastic manage to get into a sealed engine that has never been opened 2. How does a plastic pass through all filters and end up by the valves. I asked for the pictures until this day I don't have any. 3. This is not for the first or second time that when my car goes to Renault Silverlakes brakes a day or 2 after service, but now it is for the 3rd time. 4. Another gentleman who has the same issue with the same dealer and the same car says he is experiencing a similar problem with the service dealer. I am pleading with the public if u have any idea or how to deal with this matter please help. I've now contacted the Ombasdman awaiting for response Bare in mind the car was functional with no warnings or issues but suddenly when it came out of the service dealer it broke.