Charged for device when contract has ended

<p>Please refer to invoice number ********** 479. I have been charged for a device on ********** when no device was taken. This contract ended on 31 March 2017 and I changed the contract as it expired from a smart plan 100 to a Free Me 1GB. I have been incorrectly charged for a device subscription fee on this contract as I took no device on the Free Me 1GB and the BB Z3 taken on the smart plan 100 was paid for at the end of the contract on 31 March 2017. Also Number ********** 618 was meant to be cancelled on expiry of the contract at 31 March 2017 and I see they have not charged a device subscription fee on this number but they have continued to charge for the smart plan 100 - please refer to reference number ********** 4 which was logged on 27 February 2017 for cancellation of this contract. URGENTLY ASSIST AND ADVISE!</p>