Billed me after I cancelled their services

I cancelled my ADT Security Services on 9/10/15 by email. I have proof of the email sent to them. ADT did not respond and again deducted the monthly premium as well as the annual radio fee ( I presume) from my bank account on 30/11/15. I have in the meantime stopped payment at my bank, but because ADT changed the amount from R514-08 to R770-08, it went through again. They even submitted the R514-08 again in December, which my bank stopped. I want a full refund of R770-08 from ADT as I did cancel my service a month in advance. ADT ignored all my emails in this regard. Thank you!