12GB of 200GB or 10GB of 100GB can be used for EU roaming depending on which membership you have.
Once you hit the relevant EU roaming data limit you get the message that you received.
I'm not sure but I think that if you buy a data add-on then you can use that data for EU roaming.
You might want to check with 48 support to be sure before buying an add-on though.
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