BUG #15213: unable to login on PostgreSQL by postgres user

The following bug has been logged on the website:

Bug reference:      15213
Logged by:          dhirendra singh
Email address:      dhirendra04@hotmail.com
PostgreSQL version: 9.3.17
Operating system:   Centos 7
Description:

Hi Team,
I need your assistance on below error.
----------------------------------------------------------------------------------------------
[dhirsing@jira-stg ~]$ sudo -u postgres psql postgres
[sudo] password for dhirsing:
could not change directory to "/home/dhirsing"
psql: FATAL:  database "postgres" does not exist
DETAIL:  The database subdirectory "base/12950" is missing.
-----------------------------------------------------------------------------------------------
I was able to log in to this server before a few days now I am not able to
log in due to above error.
I am sharing error log file for more information, please advise me the
correct process to get support from Postgres support team in case I am not
following the correct process 

Regards,
Dhirendra