Hi Jeslin,
To recover password:
1. Connect to controller using Console Cable
2. Reboot the controller and wait for Login prompt
3. Enter "emergency" without quote as username and after that it will give two option i.e.
4. reset password, select 1
5. after that it will give same prompt, select 0.
6. now you can use default username and password i.e. admin/admin.
Please try this and let me know the reasult.