Depending on the damage or groves put into the spindle, I would try to sand it smooth.
It may take you awhile Joel but with some emery paper you can do a pretty good job.
If you have a caliper, check the spindle size every so often to see what you have done. If you need a measurement to know when it is close, measure the other side if it is not also damaged to some degree.
I cannot believe they could not weld a new spindle on to your existing axle.
We had one of our race trailers go bad with a bearing in Iowa and we took emery paper and cleaned it up enough to get home we thought. The next day we checked it out and it seeemed to be fine and we used it for 2 more years that way.
The shop we stopped at in Iowa said the axle had to be replaced.
There are times when I believe some of these shops make the issue to be much worse than what it really is simply to make a few more dollars.
You have nothing to lose by trying to smooth it out with some emery paper. Don’t use anything rougher than emery paper as you could put some small grooves into the spindle.
Then fit your bearing to the spindle to see how it fits.