My new tire was swapped with an old tire and my car was not fully serviced.

I'm having a problem with VW Midrand, my car had a problem with clutch and i took it to the dealership because it is under warranty, unfortunately my claim was rejected due to wear and tear. I had to fix my car which i paid R 8100. 00 and it has been there for a month, last week Saturday 30/11/19 i went to collect it and i found out that my left back tire it was replaced with an old tire and now my car is leaking oil and they want to charge me for that and that was caused by their mechanic.