Mercedes the Glen have damaged my car and refuse to accept responsibility for their part

I recently have taken my car to my dealership for a service. A week later my engine light comes on and the next day my car won’t start. This is pecu**** because it was working fine before the service. Nothing faulty was reported at the time of service as well. Now I am being charged an arm and leg to repair the car. I really don’t have the money to repair the vehicle at such high costs and I get no support from the dealership. My car has always been serviced at a Mercedes dealership and I have full service history. I am highly disappointed and feel that had I not taken my car for a service my scar would be running fine right now. Also the manager was not helpful. I had to call them more than 4 times to follow up on whether my car arrived at the dealership and what was going on with my car. They easily say that it’s not their fault. This doesn’t seem reasonable to me.