My mobile cannot be used in abroad (within the EU) even though the data roaming was verified, it was connected to one of the local network providers automatically, and received message that “Datenroaming in XXX kostet in Ihrem Tarif so viel wie in Ihrem Inlandstarif. Schöne Reise wünscht Ihnen o2!" kind of message.

I am not sure whether my data roaming in abroad is locked or it was just because bad network issue.

Although I tried the customer service hotline for several times, it was all in German and I couldn’t understand how to do. Also I went to the O2 shop but the staff was too unfriendly to let me know anything just playing with his phone.  

It is very appreciated if someone has/had a similar experience and give me any clues.

Best regards,