|as i previously posted, i agree STRONGLY that oil additives are a terrible idea, but i think the biggest issue here is that the stealership threw it in and charged the OP for it without asking.
its one think if someone adds an oil additive of their own accord, then the consequences are on them. personally i would demand an oil change to get that krap out of my engine.
in all my years of car ownership, no one, other than myself has ever changed my oil. that decision is validated more now than ever.
i would def. write to vwoa and tell them whats going on. its bad enough when i read about people who bring their gti to pep boys to get the oil changed and it gets ####'d up, you should be able to trust the dealer.