There isn't one, you use Help & Contact, but unless you want something that only ebay can deal with (your account for example), you would do far better asking on here. You will get a fast answer and more accurate than from Ebay CS.
You must understand that many ebay CS staff do not speak English as their first Language and answers are read from Scripts. If not covered you are likely to be told what you want to hear, not a helpful answer.
