What does the weight of the bag have to with it? I can overstuff a small bag with 100 lbs or bricks, or overstuff a giant bag with 15 lbs of feather pillows.
Just because you can stuff more stuff in there doesn't mean it wasn't overstuffed.
Since you say
Was the bag overstuffed: depends on your definition.
I'll assume you are saying there was a chance you overstuffed it. I don't think you will get anything from them, their definition was it was overstuffed.