Hello Su,
Thank you for your question about your eBay UserID. We record the ID exactly the way that eBay gives it to us. I suspect that eBay allows you to log in without the dash, which leads to some confusion. You cannot change the ID on our side, unfortunately.
Please let us know if this did not resolve your issue to your satisfaction, and we can take the next step. We are happy to help.
bidslammer