I am sure VF the company are in the right here, but a VF representative told him that he can change up and back down with no penalty. If the rules had changed within the 4 months of the original change then I cant see how VF could hold them to the charge. If the rule was there before the original plan change then the store should be held accountable.

As per the OP even the store themselves were surprised of the charge so why doesnt the store honour the request?

Still simple.