Did you call Talktalk to set up roaming?
Otherwise you may just be connecting to the local network.
See these pages, @Sunwing:
https://community.talktalk.co.uk/t5/Articles/Using-TalkTalk-Mobile-abroad/ta-p/2204471
Gliwmaeden2, a fellow customer.
From the 29th of March our TalkTalk Community will move to peer-to-peer support and the TalkTalk team will no longer be here to support with queries. Don’t worry we still have plenty of ways to reach out if you need to speak to TalkTalk directly. For more details check out the link in the post at the top of any forum message board.
