There would be only few who would be happy with their works.
Otherwise they are famous in blocking you on their social media pages.
They don't give contact details of higher authorities.
If your luck is good, it will get resolved at customer care else you have no other way to get things sorted. Even my brother faced similar bad experience.
He have to threaten service centre owner as they were not providing services in gentlemen way.
And regarding Sony Mobile, he contacted Pehredaar of Network 18 channel.