spring seat

I was wondering if anyone could give me some info/advice on a 1996 E320.
Two nights ago, I was driving and I felt like I hit something, like a road cone or something.
As I drove, it felt like something was scraping when I hit a bump. I drove it right to the MB garage and got a preliminary (Saturday) diagnosis: the spring seat rusted and the body shot has to weld it back into place.
How drastic is this? He said I did not do any damage to it by driving it in. I went looking online and can't find anything about the spring seat. I assume (duh) it is the part of the frame the suspension sits on but that is all I can assume. Anything you can tell me in the way of info or advice would be greatly appreciated.
Thanks,
Patti in Ohio