Billing cancelled contract

Contract cancelled due to very poor service, repeatedly, last straw was March 2014, there was no reaction after phonecall for assistance and other security company reacted and arrived two hours before Chubb. E-mail to confirm cancellation was sent to Chubb Nelspruit ,and was/is ignored till today,they insisted on 3 month notice I am still being billed via dt order and have discussed the issue with local and headoffice staff from Chubb on numerious occasions but with no result. Chubb need to refund me all the deductions and bank charges from March 201 to date.I have just received a inv/statement from Chubb dd. 1December 2015 showing a balance outstanding of R2768.45. Last entry 15/07/2015 R251.50 but I have a DT/order payment dd. 02/11/2015 of R320.00 on my bank statement.?<br> Chubb must refund all deductions and bank charges from date of cancellation to todays date.<br>