This problem has only just started withing the last few hours

Everytime i go to connect to the internet i keep getting a message saying "Could not activate cellular network data" or it says the server has stoped responding

However on wifi its fine, but on g3 its pish

Iv did all the usual stuff like network reset, sync and hard reset and its still the same

Anyone else got this problem, think im gonna take it back down the the o2 shop tomorow