NHTSA Complaint #11430557 — 2011 CHEVROLET SILVERADO 1500

I brought my truck into a certified Chevrolet repair facility for routine maintenence and to have a repair done on my gas tank. Upon pickup of my vehicle, I noticed that my airbag alert light/ indicator was illuminated on my dashboard. I quickly re-entered the repair facility, and asked them why is my airbag light now illuminated, as it was NOT illuminated prior to this visit. The service manager told me there was a recall on my passenger airbag, so they took it upon themselves to install a new one, causing me to now have a "Service Airbag System"message on my dashboard, along with the illuminated Airbag indicator. My vehicle is equipped with "Onstar", which is a very useful tool that gives me real time diagnostics on my vehicle. Through documentation, I can prove the airbag system did NOT have any issues prior to them installing the new one. They did not notify me that they were going to do this recalled airbag. They are refusing to take accountability and liability for what happened to my vehicle. Please help.