What if I marinated beef with oyster sauce, salt, sugar, soy sauce, garlic and onion but put into freezer for 3 days. Is it still good to eat?
As far as safety goes, you're fine, assuming the meat didn't stay unfrozen for too long before you refroze it.
As far as the efficacy of the marinading process, I'd think that the freezing/freezer burning process would go a long way toward preventing the marinade from imparting a lot of flavour and/or tenderness. Still, 3 days frozen is nothing. Shouldn't hurt anything.
Safe yes, as long as it wasn't left at room temperature for too long, but you are not taking advantage of the benefits of a marinade by freezing (as mentioned by @Satanicpuppy). Can you not leave the marinating beef in the refrigerator? Three days is pushing it, maybe, but two days in a marinade shouldn't be a problem in a nice cold fridge.