Toyota Elegant Persistent Bad Engine Error

Hello,
I am a user of a 2009 Toyota Elegant. Two years ago, I went to the Gebze Aykon service center for a noise complaint. After disassembling the car and conducting an inspection, they diagnosed a burnt gasket. Consequently, the vehicle underwent rectification. However, after starting to use the car, an excessive oil loss issue arose. As a result, the engine was dismantled three times within two years. Yet, the problem remains unresolved. I was called in again for another engine dismantling. I want to sell my car to upgrade its model. However, due to the unresolved issue, I cannot sell my car.