Your old account should still be active, you can call eBay and they can help you restore it. Or you can try to log into the old account and when you are asked to reset your password, choose the phone method or text to get your PIN for resetting. You should wait few minutes for the pin to arrive, if you click on resend pin, they will send you a new pin and the one that you would receive first will be inactive, so if you click on resend pin more than once, make sure that you enter the last pin you receive.
But if you call eBay customer support, they will help you in cancelling the new account and just keeping the original one.