I presume that you're roaming in the EU and calls and texts work but data does not?
That being the case check your APN settings and if the APN field has changed from 48months.liffeytelecom.com to something else, edit it, change it back to that, save the change, reboot the phone and check if data starts working.
It's a common EU roaming problem and that tip fixes it for many people who are affected.
Hope this helps.
