I am so frustrated with RCS!!!

I am beyond frustrated with RCS. I obtained a settlement figure from RCS on 30 June 2015 which I paid the same day. I called to confirm that all was in order and I was assured that it was. I requested that the debit order be cancelled and again I was assured that it was. On 27 July 2015 RCS deducted an amount from my account. I called RCS and I was assured that the account was paid in full and that the debit order was an error and that I should ask my bank to reverse the debit order which I duly did. On 9 August 2015 I received an sms from RCS: \YOUR RCS LOAN ACCOUNT IS OVERDUE. PLEASE PAY TODAY