hi there !
i dont think ur problem is something big,because its talked about acc ,and u jus need to makae sure that you are typing the informations Correct.
or think if u have changed before Name Or Password of Account.
If not.
you have a chance to consult with Administrators,they can help u to get back ur old account,ofc if you're the leader of that acc.
atleast make sure to trun caps lock off or on how its ur pw.
i hope u will understand me,bc i dont have what to say about this.
better consult administrators,or make sure u have changed something before.
+ u can see in taht Screen "Forgotten Password" so u can press here and with the email that u opened that acc,u can get a new password of account.
just needed gmail. Its simple !
any help please feel free to contact me via pm&ts3
Best Of Luck !