You have to rename all
@model OnlineShoppingSystemMVC.YourModelsFolder.YourModel
to
@model OnlineShoppingSystemMvc.YourModelsFolder.YourModel
in all your View files
Right now I did what you did before (I renamed the namespace of one of my projects (ctrl+ R)) and all the namespaces was renamed but the models' namespaces in my Views didn't changed.