Probably, they mean with "losing" to have no access anymore and no possibility to get it back.
OT: Please contact accounts@ppy.sh and explain your situation there. If you remember your old e-mail address but having no access to change please mention that. If you do not remember do also mention that. The more informations you can provide the faster they can help you. And last: Do not create a new account. You may risk your accessibility in this game.