you need to enable WEP or WPA encryption. Otherwise anyone with a computer with a wireless NIC or a WI-FI ready laptop can utilize your Internet account, OR worse yet get into your computer to steal private information like passwords, credit card #s, bank account #s, etc...

All it takes is some yo-yo driving around your neighborhood with a WI-FI fired up "sniffing" for open hot spot. Once they find one they can get into, they can glean all kinds of info from your system in a short period of time.

I don't know if this has happened to you or not but it would appear that someone has hijacked your eBay account so you need to contact eBay to find out what is going on.

Cheers!
Bill