Impossible to resolve a billing query

My wife cancelled her ADT-service in November 2014. As per ADT's communication, she still paid until end January 2015 every month's service. On 17 February 2015 ADT confirmed by email that R203,33 is outstanding - that was paid on 28 February 2015.<br> Then in August 2015 she receives a bill that she still owes R247,00. After numerous emails to ADT, they confirmed in writing that nothing is outstanding. A month later we were handed over to Debtsource...after sending them all the emails and information, they are unable to understand it, and keep on harassing my wife for monies not owed!!!<br> Now we receive a mail from Debtsource, dated 3 Sept, but only sent on 11 Sept, then giving us 10 days from date of the letter to respond. Now we apparently also owe them R550,00 for a decoder!!!<br> <br> It appears ADT can only make money by ********** transactions and bullying? <br> Such pathetic client service must be a new low-level, even for ADT. It appears that no one at Debtsource know how to do their work. Why are the people paid for a position which they are not capable to occupy?