Face Time Not Registering My E-mail,But Phone Number

Hi Guys,

I bought 1 brand new iPhone 4s 32GB last week which works flawlessly till now.

I am really happy with it except only one problem which is Face Time thats very important function for me here.

As per the searching results in the community,i found many members are struggling with Face Time Activation.

I was also facing Activation issue in the first few days both for iMessage and Face Time.

But, both were activated together a day when i continuously pressed sign in. iMessage started to work once it showed 'green' sign.

but, Face Time didn't .

the problem i found that in Face Time, only my Mobile number was added and people can reach me by my number only. still the option to 'Use Face Time by Apple ID' is present in Settings>Face Time.

Also, when i am trying to Login, showing either 'an error occured while trying to activate' or 'sign in error , please check your internet connection' even though i am entering correct login details.

i am receiving Face Time calls, but, once i attend the call , it disconnects or showing 'connecting.....'

what the problem would be ? i am iOS 8.4

waiting Experts' reply.

Thank you Guys