Have you paid?
Don't, yet.
Use Contact Seller on the listing to ask about sizing. You should have done this before bidding, but we live and learn.
Whatever your size is , go up a few. The Chinese cannot believe how big North Americans can get. I have ordered three sizes larger than my usual, matching to listed measurements, and still recieved items that are too small.
If he does not respond, ask for a Mutual Cancellation. If he does not respond, Report him to eBay for invalid contact information.
Don't ever pay for anything from China unless you are willing to return it with Delivery Confirmation for a refund. DC shipments to China start around $40.