The right way? It's the name of the product. That's it. That's how the inventor/creator decided to spell it. Spelling it with an "F" is the wrong way bastardization of English or not because that's it's actual name. Really though, why even care? Do you correct people who spell Jeffery "Jeffrey" or Brian "Bryan"? Would you guys be making a big deal if people spelled out AF as "I'll fuck *hock a loogie* here"?
Actually, don't answer that, especially if you're a mod.