The problem occur is within the area or every where?
Did you try out:
1) Connect to your home Wi-Fi
2) Connect to outside Wi-Fi (please be careful for some un-secure issue)
3) Data sharing from different phone (try connect your data by using your friends or family devices)
4) Connect your Telco simcard outside the area where you said is not working
If everything above is not working, i believe you should visit Samsung service center as vyan mentioned. But before the visit, try ask your Telco first because i am sure once you go to Samsung service center, they might throw the issue back to Telco (make sure you have a report from Telco that it is not cause by them at least).
If you so confident is a phone issue then is time to ask them about it.
In case you want to chat/ call with them first, here is their contact details:
Hope they can solve your issue asap.