Forgot to Fill W-8BEN—Charged 24% Withholding Tax! Will I Get a Refund?

I’m a non-U.S. citizen and non-resident using Schwab. I forgot to submit my W-8BEN form and sold some stocks yesterday, which led to $2,800 being withholding taxes!

I just submitted the W-8BEN, and Schwab support told me—twice—that I should get a refund within 14 business days once the form is processed.

I’m really anxious—has anyone actually received a refund this way? I’m worried they might not pay me back, and I don’t know what to do if that happens. Any advice or similar experiences?