Just because the phone has been stolen does not mean you can cancel the contract @Angelikaw
You need to first report the phone and sim as stolen - o2 will then send you a replacement to the address on your account.
Guide: Lost or Stolen O2 Device? - How to Report it
If you are out of the minimum period for your contract, then you can cancel:
Guide: Cancelling Your Contract
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 Do not publish personal details (email, phone number, bank account).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
