Welcome to the community and thanks for posting. I deeply apologise for having no mobile service in Cyprus. I appreciate how important it is to be able to connect to friends and family back home.
The first thing I'd recommend is restarting the handset if you haven't done so already. After that, You can try searching for a manual network by following these steps:-
Settings > Carrier > Select network
If that fails, then the next step would be to call technical support. The number you need to call is +447953967967. Alternatively, you can speak to our web chat team.
Hope this information helps. Please let me know how you get on with that.