FRESH oxtail

So I bought 5 x packets of oxtail very neatly trimmed etc. But I should've known when all the fat was trimmed off. Must've been yellow fat (old ox). WHY in heaven's name was the oxtail pickled (or filled with nitrites?). After 7 hours it was tough with a pink hue of corned beef and smelled like bully beef. You can fool some people some of the time but you can't fool all people all of the time. THAT was **********. THE most disgusting oxtail I've ever cooked, but then, I have very high standards. I think you've been getting away with it forever, else why would they be sitting on the shelf. Packaging resembled that of woollies but ugh. WHO pickles ox tail?