Touch screen not responding?

Hi, I have an Iphone 5S and have a little bit more than a year,

Like 3 weeks ago started failing that I could see the screen but didn't recognized the touch or the actions that I wanted to do, I solved that putting the brightness down.

But now, like I can use it for a minute and then doesn't recognize the touch anymore. I must say that the problem started since I updated the 9.2

I'm currently at the Czech Republic and in the store they told me that I must restore the cellphone but I didn't help.

I write in this Forum because actually nobody knows what my cellphone has.My cellphone is everything good, hasn't fallen and the screen is not cracked