The representative office is basically an office (or similar) where a foreign company can place employees, controlled by the main office, can perform any type of sale.
Can perform any function as the main office out of Russia with the exceptions that can't import or sale products, it can only sell services.
A fully regular company that can (with use of licenses) approach any types of (legal) duties, the LLC and it's shareholders and directors are fully liable for the company's actions.