On Linkedin I have posted the above question and mentioned some of my most well known Linkedin Expert connections.
AJ Wilcox told me this:
A friend reported chatting with them last week. I'd imagine it's an employee out of San Francisco for help with ads platform, so check it 9am-5pt pacific time zone for the best chance of getting someone.
I've realised that I have wrote a Linkedin Article back in February 2016, about DIRECTLY, Linkedin just purchased back than.
Brynne Tillman told me, I should use Twitter and use @linkedinhelp to get help. It works perfect, but if that does, why doesn't the chat working.
By now I have 3,300+ views, 6 likes and 17 comments. I know this isn't a very well read post, but quite strong in my terms.
And suddenly it started working perfect. So I asked Denis, my Linkedin Help Center assistant, when are they available. And she told me "7-7 CST, Mon-Fri", which might relate to a 7 am to 7 pm Central Time Zone (see image below), Monday to Friday.
I have mentioned to Denis, that most of the Linkedin users/members live outside the US. She never replied. According to Linkedin (bit.ly/DrLinkedin_OR_NOT_DrLinkedin), there are 558 million Linkedin users recently, and on 148 million of them are in the US, this is 26,52%, a bit over a ¼.