If this is not showing on your Ebay account, did you buy as a guest?
The link below will get an online chat or a callback so you can report the issue with accessing the label. However, you do still need to be within the time allowed to return the item. When does it say it needs to be returned by in your opened case?
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)