Bill higher than expected

[C11]

I went in Romania for a few days and I used the Sim card from UK for Internet and calls. The calls were not working. I received a high bill for my Sim card and I am not sure what happened. I spoke with someone from O2 and I advised them that I was going in Romania and if I can add anything to my account to make sure I don't have extra costs for when I will be back. Now my Sim is not working and I can't use it anymore. I have a high bill to pay and I don't understand why. Can someone contact me for details on how I can cancel my contract and what I have to pay regarding this? On the website it showing that I was supposed to receive messages that the payment for the Sim was not successful and that they will try again. I never received a text like this. Please provide me details on how I can cancel my monthly payment and what fees you have for this again.

Thank you 

Miss Cristina Cătană 

[MI5 · Accepted solution]

@C11 

This looks like something you’ll be able to do or check in the My O2 app. We have a guide to help with that if you’re unsure how to use it Guide: How-to guide for My O2 And don’t worry if you get stuck because there’s an in-app messaging service you can use to chat with O2 who can help. Just go to the ‘Support’ tab and ‘Start a Conversation’ at the bottom.
If you still need help then the Social Media teams will be on hand, just send them a message on Facebook (https://o2uk.co/O2CFB) , Twitter (https://o2uk.co/O2CTW) or Instagram (https://o2uk.co/O2CIG)
Thanks