Accused of utility model patent infringement, but the product is represented by a company, what should I do?

Question1:Company A only represents the products of Company B. Can Company C sue Company A for infringement? Yes, selling infringing products is also infringement. Question 2: The products produced by Company B have been produced and used in the project in 2009. Company c sued company b for infringement. Can Company B sue Company C for patent invalidation through "preemptive right"? To analyze how the patent claim is written. If there is an improvement, which is not a known technology, it may only be partially ineffective. The same is true for judging whether there is infringement. If you want to argue with the existing technology, you must prove that all the technologies you use are public technologies. Or have been produced, sold and used before the patent application.