Telkom refuses to cancel service of address I no longer reside at and keeps on billing me

I notified Telkom in September 2017 that I am changing residential address and wish to cancel my fixed line service (phone and ADSL) with them. I checked in October whether it was cancelled and I wanted to get my R700 deposit back. The services were not cancelled. I telephonically and via email then contacted them to address my grievance, filling in yet again the same cancellation forms. I must have phoned the call center and spoken to 6 different agents since. I've sent multiple emails directed to specific agents at Telkom and have yet not been successful. I moved residence at end of November and have since been billed for December and have received yet another bill for January that will be deducted soon. Telkom has ********ly debited money from my account and are threatening me that they will continue to debit money from my account. They refuse to cancel the service, keep on debiting my account, and do not want to pay back the deposit they owe me, as well as the money that they have ********ly taken from me.