The IP your router is showing is your local IP. The IP on whatsmyip.com is what eBay and the likes can see.
If you turn the router/modem off (or just unplug the internet cable from it), wait a few minutes and plug it back in, does the IP on whatsmyip.com change?
Routers are $20 and this method does work for Comcast. I cannot comment on TWC, but for $20, it's worth a shot. Or pick up a few on Crai.gs.List for cheap.
Routers are $20 and this method does work for Comcast. I cannot comment on TWC, but for $20, it's worth a shot. Or pick up a few on Crai.gs.List for cheap.
Changing router won't change your IP if it's static.
A quick google seems to indicate there's some kind of pre-allocated DHCP going on so it's difficult to get TWC IPs to change (I don't use the ISP, someone else might be better informed)
Have you tried releasing & renewing on your router? What make/model is it?