I was in Poland and I couldn't use my data roaming because there was no coverage even though I had a text message from O2 saying otherwise, terrible service !! My wife is with EE and she had no problems at all with browsing and making and receiving calls, also I can never get network coverage and data when I'm working in the countryside, I'm very disappointed and I want to leave O2.
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion. This is not Customer Service so we are unable to help with account specific issues.