Body filler shrink!

[Rgee]

I had some bodywork and paint done to both rear quarters on my car in January and one side needed some filling, for blending in rather any big dents. I noticed last week that there is some shrinkage in a small area so I took it back to the bodyshop and they said they can polish it out while I wait but they can't do it for a few weeks. Can shrinkage be polished out? I'm struggling to think how in my simple mind as the filler is sitting below the top coat and lacquer. I know that wet sanding can get rid of orange peel but thats imperfections in the lacquer.

[Rgee]

Thanks, I'll what the bodyshop can do in a couple of weeks.