When was the last time you used the old account? eBay does purge accounts after a long period of inactivity - they send you an annual reminder to login to verify your info so your account remains active. If your account was purged, there is no way to get it back.
If it has not been years since you used it, try signing in with the email address on that account and click forgot password. eBay will send you a link to rest the password to gain access to your account.
If the old account had the same email that you used to open the new account, then the old account is permanently gone - you can only have 1 account per email address.
wooden_flower Volunteer Community Mentor.
eBay member since 2001.