Help Samsung Galaxy S4 time/notifications problem

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Hello,
I am having the following problem for several days now:
I do not get any notifications via facebook.I thought that was a minor problem,
but I think it is caused by something different.
Because everytime I send a message to someone via the facebook-app it says sent 17:20, no matter what the actual time is.
Enabling the phone to get the time automatically or just set the time does not make it any better.
I thought the problem would only affect the facebook-app but now I sent a sms and it also says that its sent at 17:20.
And that causes the app to fail to sort the most recent messages, because after sent, it places it somewhere in between messages where 17:20 fits in.
And thats why I think that the facebook notifications are not working properly, because it is not noticed as such, because since its always recieved at 17:20 it does not recognize it as recent message.
It is very difficult to explain, and even more difficult to find someone who posted the same problem already, I hope you understood what my problem is.
I even updated my phone because of that, hoping it would fix that problem

Thanks in advance