Refuses to cancel inactive SIM/contract

They are refusing to close/Cancel a contract after I requested them due to not being able to use the SIM card because it has a barring. They instead keep sending me statements of zero usage, how does that even make sense!!! I even opted to get their router as a solution so I can use their SIM, but that didn't even happen as they keep opening and closing cases with no resolution. Their complaints dek doesn't even care to respond, I have resorted to go to the ombudsman. If you had planned on using them, friendly warning DO NOT!!!! Bunch of ******