Punky, you can't have capitals in eBay username, so I'm guessing the OPs former username starts with a lower case L

OP, I know it's a few days since you posted, but try logging into your other account using your Facebook email address and password, rather than clicking on the sign in with Facebook button. If that doesn't work, just use your new account. Most sellers don't have an issue with low feedback buyers, and if what you buy are buy it now items, there's not really a lot they can do about it anyway, even if they did care.