No confirmation of cancellation

My ADT contract has expired and I've tried to cancel the subscription at these dates:<br> Jul 20 - Phoned local ADT branch, spoke to Jackie Boshoff, she said I can just formally mail my request for cancellation.<br> Jul 20 - Mailed Jackie for cancellation - no response<br> Jul 21 - Mailed Jackie asking to confirm my request for cancellation - she responds saying request was forwarder to HQ<br> Jul 27 - Mail Jackie to ask why no response received yet - she didn't reply<br> Jul 31 - Mail Jackie and HQ to ask why no response received yet - no reply<br> Aug 2nd - ADT bills me for August and deducts via debit order as usual.<br> <br> To this day (04 Aug) I haven't received a response from either my local ADT branch or the ADT headquarters