Gee, well I'll tell you what you probably SHOULDN'T do, and that is post a photo of the violation on a local gun forum read by most of the local ATF agents with the name and location of the store. The rules about VFG on pistols are not widely known and an honest mistake may have been made that someone is now in danger of losing their business and going to prison over. Or, perhaps it is properly registered as a Class III firearm.
I would delete that photo and call them ASAP.