
Best answer by WelshPaul
It’s likely that you either connected to a country whose border you were near, that’s not included in iD Mobile’s inclusive EU roaming package, or you travelled through one of these countries.
Or, it’s likely that you were charged for going out/near to the sea, and connected to the maritime network.
I’d recommend contacting iD Mobile’s live-chat to investigate these charges further for you if you need:
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