As mentioned press the axle out, or just cut the carrier off. Where's your existing carrier? Why did you need to use the set up you got for free? Get fresh bearings and seals for whatever you use, they're super cheap. If you don't have the existing carrier to use, ask on here I'm sure someone will sell you one for cheap. And FFS if you can't remove the carrier from the axle, and things aren't functioning as they should you definitely don't try and bolt it up, I'm not sure there's any bigger sign that there is or going to be an issue somewhere... LOL
Personally, I would save up and as Zilla said buy new shit but that's just me. I prefer not to work with junk these days..