Pesala, It is quite common for someone else to have the same name, When using the internet you will have a unique *User name and password*. This is the one you use to connect to your ISP.
When registering for ebay, all you need to supply is a user name, this can be the same one you use as explained above or once registered, ebay will e-mail you a account number to log on with.
You do not need to give any personal details, (Other than your e-mail address), to ebay and certainly not your real name/address or financial information, such as bank or credit card details. J.