Bad service

My VW golf's head gasket went and Bosch quoted me R26 220.80 to have the engine stripped, overhauled and diagnostics done. 4 weeks into the job, I was contacted and informed that I need to pay and extra amount which brought the full amount to R27 373.96. All monies are paid. After numerous phone calls I was informed on 18\9\19 that my car is running and ready for pick up. On Sat, 19/9/19 I arrived at Bosch to fetch the car. She was not cleaned but I signed the paperwork and left. Went to put petrol in and the attendant told me that there's oil in the water. Went straight back to Bosch. 6 mechanics under the hood then informed me the problem is with their engineering problem and the engine would again have to be stripped and redone. I am a single mother and teacher and this has cost me a fortune and now I have to sit without a cat for another 5 weeks? seriously unacceptable