Damaged my engine

Took my car in for service and when I got it back the oil seal was not closed properly which leaked out all the oil and resulted in my engine being damaged. My car is still pretty new and now they are refusing to give me a new engine and instead are insisting on reconditioning my engine. I have reported the matter to Mercedes benze SA on several occasions but all they do is keep promising to call me back but 3weeks after the incident I still haven't received any feedback from them. What a disappointing service I am getting from Mercedes benze!!'