s600tt

I have a Mercedes-Benz s600. In late September I replaced my pulsation dampner hose. Before I left the shop my tandem pump was tested multiple times and tested good. I never had a problem til now when my pulsation dampener hose blew out. The Mercedes tech informed me that it was a defective hose and it killed my pump in the process. They are going to warranty the hose due to the defective part, shouldn't Mercedes be responsible for my tandem pump as well?