I can't seem to remember the name of the product now, but it's the thing that you put under your sofa cushions to keep them from sagging. We just bought our sofa last year and it's already sagging in the spots we sit in the most. I hate it because the sofa still looks like brand new. Has anyone ever tried these or know if they work?
Is it due to the springs or the couch pads themselves? The product is called Furniture Fix, but it's not going to help if the couch pads are simply going flat. You could also possibly replace the padding instead. Some couches can be unzipped for cleaning and for replacing the padding. The reviews I read on the Furniture Fix weren't very good either. You could also possibly damage the couch further if they happen to crack and tear into the couch base.
I too have heard mixed reviews on Furniture Fix. I had a friend who used some light grade plywood under the cushions but it was a much older couch. In your case if the couch is less than or about a year old, I would call the furniture store that sold it to you. Some have some very good after the sale serviced...It doesnt seem right it should sag that bad in this period of time.