I would still use it, but 1) I like to live close to the edge, and 2) I'm cheap.

More seriously, I don't cook for anyone very young, very old, or with a compromised immune system. What you did will definitely damage the quality of the meat: the rapid thawing and the refreezing both cause it to lose moisture. It is possible that it could spoil more quickly the next time around, which is why it shouldn't be served to anyone I mentioned.
If you do choose to thaw and cook it, consider time and temperature: if you want to thaw it quickly, do it under running cold water. If you can take the time, thaw it in the fridge. Then cook it as soon after thawing as you can. And cook it thoroughly. Rather than use it for a roast and cook it to rare, consider cutting it into cubes (which you can do even before it is fully thawed) and using it for a stew or braise in which you brown the cubes first and then simmer for a long time. That will also take care of the lower moisture content. But again, don't use it if you want to serve it to someone who could more easily get sick.
That said, if after you thaw it, it smells really bad, or it has an off color (that greenish, iridescent cast to the surface), THROW IT OUT.