I can’t log in to my account using my username and password even if I memorized them what do I do

[kimtabat]

I can’t log in to my account using my username and password. I can’t use my email cause I forgot what email I used. Even though I know the username and password are correct it said it is not correct. Pls help me Cuz I just paid Premium for that account

Plan

Free

Country

Device

iphone 7 Plus 

Operating System

(iOS 10, Android Oreo, Windows 10,etc.)

My Question or Issue

[Onewave]

How did you log in to post a message here, may I ask?