I tried all kind of solutions, but it didn't work.
I've made the time zone thing.
I tried to restore network settings.
I tried to restore and erase all content and set it as a new iphone.
I tried to change the DNS number.
I tried to reenter my phone number at the Apple ID webpage. I tried to erase it.
I tried to turning off the wifi conexion, And I have wait 24 hours to activate. Nothing seems to work.
I had a chat with apple support, they told me that is a software problem, that I have to call to apple's phone support, I can't do that 'cause I live in Chile, so there is no apple's phone support in my country. I thought that if is a software problem, I can downgrade the IOS to 7.0.3 or later, but I couldn't, my Iphone 5s didn't recognize that software.... i don't know why, I guess it's because we only can make an upgrade...
The thing is that before a bought this iphone 5s, i had a Iphone4s and facetime and imessage worked perfectly on it. I bought it with the same network carrier. When I changed the phone, I restored the 4s iphone as a new one, so I don't have an Apple ID working on different iphones.
I really don't know what to do. 😢 HELPPPPPPPPP