general problems of the 2006 Nissan Sentra

Bought a 2006 Nissan Sentra from an individual as a first car for my grandson. Drivers seatbelt does not retract. Took to body shop and they said it was a safety issue and we would need to take it to the dealer. The Nissan dealer in chattanooga said that they could not repair it as the part was discontinued. Did not give us an alternative other than to to google it and fix it ourselves (but it's a safety problem that even a body shop won't touch). So now my grandson has his first car but it's worthless?.

I have only had my vehicle for 11 months. Last week a red flashing light appears. I looked it up in my handbook and it showed that a safety restraint isn't working. I took the vehicle to the dealer and the cost for repair is $1600. 00. Since I've owned my vehicle it has not been in any accident, and when I purchased the vehicle the carfax report was clean as well. My repair guy says that the only way the light should've come on was due to front end collision, which, I have never had. I am being told that in case of accident none of my safety features will not work. No seat belt tightening, no airbagdeploy etc. I am very concerned because I have two small children and would like to figure out what's going on. There should be no reason that an 11 month old car should be acting like this!! I have not yet repaired the vehicle, I am going back and forth with the dealer because this actual problem should be covered under the federal emissions law.