Why were you in arbitration for an auto accident case?

Why didn't you seek to recuse the arbitrator?

What does this mean?

If your attorney failed to disclose important evidence to the other side and that resulted in the evidence being excluded from arbitration, that might constitute malpractice.

No one here could possibly have the slightest idea.

If it's non-binding arbitration, then it can be disregarded.  If it's binding arbitration, you'd have to seek to have the ruling set aside, and the grounds for doing that are extremely limited.