You can call using Skype @Mulveyluke9.
There is an 0800 number in the guide below along with how to call using Skype.
Please note, this is not customer services and we cannot access your account. Do not publish personal details (email, phone number, bank account).
Link to our guide on how to contact them can be found here
Track usage, upgrade and get support with the My O2 appDownload My O2