on 18-04-2019 04:40
You cannot cancel your contract on line. You need to speak to customer services on freefone number +44344809222.
Please also be sure to cancel your airtime as well in the same phone call. 30 days notice is required for cancellation.
If you have a Direct Debit in place, do not cancel it until after you have received your final bill which will cover any months still owed to O2 to pay off your device and one month's airtime, covering your 30 day notice period.
Good luck and I hope all goes well in your new home and country.