try to unlock my phone

How is it locked? Passcode? You don't know the Apple ID password?

Passcode

Passcode - If you forgot the passcode for your iPhone or your device is disabled.    *

If you forgot the Apple ID (iCloud) password, enter the Apple (iCloud) ID, and click Forgot Password. See if you can get a Rescue or Notification email option if necessary. Link to contact Apple Support at the end of the 2nd article.

Apple ID - Manage  -     

Apple ID – Forgot Password  *