unauthorised debt in my account

last month Key direct tried to debt money from my account but unfortunately i stopped the transaction, but to my surprise they have tried it again. this month they have instead handed my account to a debt collecting company called Digi Cash. I again stopped the company. Fnb bank advised me to contact Key Direct and cancel the debit order with them .<br> <br> I called Key Direct offices on the 26th August 2015 but the call center agent has since said she will call me back but she hasn't. The company has committed ***** and I'm just another victim. The Agents have no idea what I'm being billed for, there is no knowledge of type of contract that I have taken up.